ALBERT

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 554〈/p〉 〈p〉Author(s): D. Bessas, I. Kantor, D. Bourazani, K. Georgalas, N. Biniskos, L. Zhang, A.I. Dugulan, E. Syskakis〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bulk Sr〈sub〉2〈/sub〉PdO〈sub〉3〈/sub〉 was synthesized by a modified solid state reaction and a detailed characterization was carried out using both microscopic and macroscopic experimental techniques. Pd site exhibits an electric field gradient of 5.9(1) ⋅ 10〈sup〉17〈/sup〉 V/cm〈sup〉2〈/sup〉 due to the anisotropic local atomic configuration. A Curie - paramagnetic susceptibility indicating antiferromagnetic interactions superimposed to a core diamagnetic state is confirmed. A linear volume thermal expansion with a coefficient of 3.0(1) ⋅ 10〈sup〉−5〈/sup〉 K〈sup〉−1〈/sup〉 at room temperature is extracted. A collection of Einstein oscillators, with an Einstein temperature of about 115 K, is involved in the thermal transport. Large atomic displacements were observed in Sr vibrations. No Pd or Sr valence change is observed up to 900 K. A moderate anharmonicity is identified and quantified in a macroscopic Grüneisen parameter of 2.5(1) at room temperature. The electrical resistivity reveals a semiconducting behaviour. A systematic reduction in electrical resistivity and a change in the conduction mechanism is observed upon thermal cycling which indicates that a peculiar electronic mechanism is involved.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 553〈/p〉 〈p〉Author(s): Numan Şarlı, Gökçen Dikici Yıldız, Yasin Göktürk Yıldız, Nermin Kahveci Yağcı〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effects of the Austenite (A), twinned Martensite (TM) and detwinned Martensite (DTM) structural transformations on the ferromagnetic properties are investegated by means of the effective field theory developed by Kaneyoshi. We find that the critical Curie temperature of the A, TM and DTM is obtained as T〈sub〉c〈/sub〉〈sup〉A〈/sup〉 〈 T〈sub〉c〈/sub〉〈sup〉D〈/sup〉™〈sup〉 〈/sup〉〈 T〈sub〉c〈/sub〉™ for H = 0. Thermal magnetization loops are obtained for H≠0. The area of the thermal magnetization loops of the A-TM is wider than those of the A-DTM. Paramagnetic Austenite has a phase transition from paramagnetic (PM) phase to ferromagnetic (FM) phase at T〈sub〉c〈/sub〉™ and T〈sub〉c〈/sub〉〈sup〉D〈/sup〉™. The temperature of the As (Austenite start), TM〈sub〉f〈/sub〉 (twinned Martensite finish) and DTM〈sub〉f〈/sub〉 (detwinned Martensite finish) increase as the external magnetic field (H) increases. The magnetizations of the A, TM and DTM are the same at low temperature (T 〈 A〈sub〉s〈/sub〉). The coercive field points are obtained as H〈sub〉c〈/sub〉〈sup〉A〈/sup〉 〈 H〈sub〉c〈/sub〉〈sup〉D〈/sup〉™〈sup〉 〈/sup〉〈 H〈sub〉c〈/sub〉™. The shearing angle plays very important role in the structural transformations and their ferromagnetic properties, especially in TM.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 553〈/p〉 〈p〉Author(s): A. Monamary, K. Vijayalakshmi, S. David Jereil〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, catalytic Cr metal overlayered TiO〈sub〉2〈/sub〉/ITO nanocomposite films were synthesized by novel two step deposition using spray pyrolysis and electron beam evaporation and optimized for use as H〈sub〉2〈/sub〉 sensors. The Cr stimulated TiO〈sub〉2〈/sub〉/ITO sensor showed well-defined crystalline (101) TiO〈sub〉2〈/sub〉 anatase phase with crystallite size in the range 12–14 nm. The band gap energy could be tuned from 2.44 eV to 2.06 eV, when the thickness of Cr stimulating layer increased. The anatase phase of the nanocomposites was further confirmed by Raman spectroscopy. The nanospheres shaped grains with porous morphology of the film prepared for 10 min Cr deposition time is beneficial to enhance the gas sensing activity at room temperature. The nanocomposite sensor with different Cr overlayer thickness modified the TiO〈sub〉2〈/sub〉 microstructure due to spillover effect and revealed improvement in sensitivity. The Cr:TiO〈sub〉2〈/sub〉/ITO sensor prepared with the Cr deposition time of 10 min recorded a fast response and recovery time of 30 s and 20 s, respectively, even at room temperature.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): Erhan Albayrak〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The ferrimagnetic-ferromagnetic-ferrimagnetic quaternary alloy is constructed on the Bethe lattice in the compound form as 〈em〉AB〈/em〉〈sub〉〈em〉p〈/em〉〈/sub〉〈em〉C〈/em〉〈sub〉〈em〉q〈/em〉〈/sub〉〈em〉D〈/em〉〈sub〉〈em〉r〈/em〉〈/sub〉 and formulated in terms of the exact recursion relations in the standard-random approach. The QA is designed on the BL by placing the 〈em〉A〈/em〉 atoms (spin-1) only on the sites of odd shells and randomly placing 〈em〉B〈/em〉 (spin-3/2), 〈em〉C〈/em〉 (spin-5/2) or 〈em〉D〈/em〉 (spin-2) atoms with probabilities, or concentrations, 〈em〉p〈/em〉, 〈em〉q〈/em〉 and 〈em〉r〈/em〉, respectively, on the sites of even shells. The phase diagrams are obtained from the thermal analysis of the order-parameters. It is also found that the model yields only one compensation temperature.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 553〈/p〉 〈p〉Author(s): Byoungnam Park, Hyungduk Ko, Minkyong Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Understanding correlation between interfacial charge transfer and transport at the electron donor/acceptor functional interface has remained elusive despite its impact on the optoelectronic devices because the conventional vertically stacked diode structure as well as energetic and morphological disorder at the interface complicates analysis of the interfacial region. We fabricated a test platform to enable simultaneous probing of charge transfer and transport at the nanocrystal (NC)/metal oxide interface. Using the transmission line method (TLM) in a ZnO/PbSe/ZnO test structure, we measured the ZnO/PbSe contact resistance from which interfacial charge transfer and transport properties can be correlated in relation to interfacial energetics depending on the size of PbSe NC. The interfacial transfer-transport test probe was validated by comparing size dependent energy level offset derived from the contact resistance value with the established trend. Importantly, by altering the chemical nature of the molecules attached to the NC surface, we discovered that charge transport properties including mobility in the PbSe channel away from the interface are extended into the interfacial region, enabling correlation between carrier diffusion and the electrical mobility at the electron donor/acceptor interface. With a very low mobility in the interface region, charge transfer associated with carrier diffusion is suggested to reflect the nature of energetic disordered interfacial region rather than the electrical mobility.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Song Eun Lee, The Viet Hoang, Jeong-Hae Lee, Young Kwan Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Microcavity effect plays an important role inside organic light-emitting diodes (OLEDs) due to a strong influence on the extraction of the light of the devices. In this work, the performance of blue fluorescent OLEDs (FLOLEDs) by constructing an epsilon negative tri-metal layer (ENTML) electrode is investigated. The function of the ENTML electrode is modulating the optical properties of the device under microcavity effects. The theoretical studies and experiments to evaluate the influence of the thicknesses of ENTML electrode and organic layers on the performance of blue FLOLED are presented. It is observed that the overall tendencies of both theory and experiment show good agreement. The measured results show 3.34% in maximum external quantum efficiency and 4.21 cd/A in luminous efficiency. The efficiencies of the FLOLEDs is optimized using the thin organic layer thickness of 90 nm with the Ni/Ag/Ni 2/8/2-nm thick ENTML anode.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Shengzhao Wang, Jianliang Qiao, Yuan Xu, Xinfeng Guo, Chunjuan Nan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉 system of organic-inorganic hybrid perovskite structure solar cells absorption material was established by using first-principle calculations based on density functional theory (DFT). Orthorhombic CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉 system model is optimized by different functional theories of CASTEP in Materials Studio. It revealed that the results of WC/GGA calculation method are more close to the experimental value. Electron band structure, state density are calculated in the paper and the results indicated that top orbital of the valence band is mainly contributed by Pb atom and I atomic orbital. At the same time, the conduction band bottom is mainly contributed by the orbital contribution of Pb atoms and strong σ bond is formed between terminal iodine atom and Pb atomic orbital. Moreover, the contribution of organic element density of states near the Fermi surface is very weak and the band gap of organic-inorganic hybrid CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉PbI〈sub〉3〈/sub〉 materials is basically determined by inorganic elements.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): Amarjyoti Kalita, Manos P.C. Kalita〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present work explores the differences in the various properties of Mn doped ZnO nanocrystals when the sizes of the doped nanocrystals are significantly different. Mn doped ZnO nanocrystals of sizes ≈20 nm and ≈5 nm were synthesized by the chemical co-precipitation method. The targeted Mn doping concentrations were 2%, 6% and 10% (atomic), however, the observed doping concentrations were low (≈0.5%, ≈1% and ≈2%). The microstructural, morphological, optical and magnetic properties as well as the photocatalytic activities of the nanocrystals were investigated. The variations of the lattice strain and lattice volume with increasing Mn concentrations were found to be correlated. The un-doped and Mn doped ZnO nanocrystals were found to be ferromagnetic at room temperature. Variation of band gap with increasing Mn concentrations was observed. Significant/insignificant quenching of the photoluminescence emissions was observed for sizes ≈20 nm/≈ 5 nm after doping. The saturation magnetization was found to depend on the Mn concentrations as well as on the nanocrystal sizes. Agglomerated Mn〈sup〉2+〈/sup〉 resulted in a decrease in saturation magnetization of the ≈2% Mn doped nanocrystals of sizes ≈5 nm. Correlation between the photoluminescence properties and photocatalytic activities was observed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Seyed-Sajad Ahmadpour, Mohammad Mosleh, Saeed Rasouli Heikalabad〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Quantum-dot cellular automata is one of the best alternative technologies of CMOS at nano-scale. It is an emerging technology promising to design circuits with low power consumption, high density as well as high speed. In this paper, a novel 3-input XOR gate based on the cellular interaction is first proposed which consists of 10 cells and requires two clocks. To demonstrate the efficiency of the proposed XOR gate, an optimized single-layer full-adder is designed here which contains only 20 cells and requires three clock phases. In order to verify the function of the proposed full-adder, some physical proofs and computer simulations are provided. The simulations are carried out by QCADesigner2.0.3. The proposed full-adder shows 24% and 9.09% improvement in cell count in comparison to the best previous single-layer and multi-layer full-adder designs, respectively. In addition, the power consumption of the proposed full-adder is calculated by QCAPro tool. The results of power dissipation analysis show that the proposed full-adder has the lowest energy consumption compared to the previous designs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Haiyan Zhu, Liwei Shi, Shuaiqi Li, Yifeng Duan, Wangsuo Xia, Ying Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Borides of chromium, molybdenum, and tungsten are an attractive class of transition-metal light-element compounds with superior mechanical properties. Here, we explore in detail the binary X〈sub〉2〈/sub〉B with 〈em〉I〈/em〉4∕〈em〉m〈/em〉 and 〈em〉I〈/em〉4∕〈em〉mcm〈/em〉 symmetry, XB with 141/〈em〉amd〈/em〉 and 〈em〉Cmcm〈/em〉 symmetry as well as XB〈sub〉2〈/sub〉 with 〈em〉P〈/em〉6∕〈em〉mmm〈/em〉 and 〈em〉P〈/em〉6〈sub〉3〈/sub〉∕〈em〉mmc〈/em〉 (X = Cr, Mo, W) systems by first principles calculations, especially their mechanical properties under uniaxial strains along the 〈em〉c〈/em〉 axis. We report the calculated ideal tensile strength for each structure, which is the minimum stress required to break the material. The elastic constants, bulk modulus, shear modulus, and Young's modulus are calculated at equilibrium and uniaxial strains. For the same structure, W〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉B compounds are more ductile than Cr-B and Mo-B because of their high 〈em〉B〈/em〉∕〈em〉G〈/em〉 ratio, while they fail to possess high hardness at the same time. The structures belong to space group 〈em〉P〈/em〉6〈sub〉3〈/sub〉∕〈em〉mmc〈/em〉 have the largest hardness, followed by 141-XB. Although with the highest boron content, hardness values for 191-XB〈sub〉2〈/sub〉 are much lower than 194-XB〈sub〉2〈/sub〉 phases with the same composition. The anisotropy of X-B systems has also been studied, which is rare in previous reports. The underlying mechanism for the high elastic modulus and hardness of X〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉B systems is further discussed by the analysis of electronic density of states.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): A. Stepanyan, A. Asatryan, M. Yeranosyan, K. Vardanyan, A. Kirakosyan, A. Vartanian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Within the frame of electron-temperature model we calculate the average energy loss rate due to interface and confined longitudinal optical (LO) phonon emission from a hot-electron gas to a cold lattice in polar semiconductor nanowire surrounded by non-polar material. The system both with and without hot-phonon effect is investigated. The impact of a perpendicular electric field on average energy loss rate is explored. The energy loss rate dependences on electric field strength, wire radius and electron temperature are obtained. It has been shown that the energy loss rate is more sensitive to the electric field when the wire radius is larger. The presented results indicate that the electric field applied perpendicularly to the wire axis can serve as a means to control the energy loss rate. There is an experimental evidence concerning to the increase of energy loss rate with increasing electron temperature as we have obtained.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): Muhammad Rizwan, Adnan Ali, Zahid Usman, N.R. Khalid, H.B. Jin, C.B. Cao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉First-principles calculations based on the density function theory (DFT) are implemented to explore the effect of Cu doping on the structural, electronic and optical properties of SrTi〈em〉O〈/em〉〈sub〉3〈/sub〉 Perovskite using generalized gradient approximation (GGA) and ultrasoft pseudo-potential (USP). The effects of Cu doping on the formation energy, electronic structure and optical property are discussed here. The results of formation energies infer that Cu doping at Sr site in SrTi〈em〉O〈/em〉〈sub〉3〈/sub〉 is more favorable as compared to Ti site. Cu incorporation at Sr site affects the electronic band structure of SrTi〈em〉O〈/em〉〈sub〉3〈/sub〉 significantly by introducing new states at Gamma point consequently transforming its indirect band gap into the direct one. The relocation of density of states to lower energies, and an increased interaction between Cu atom and its neighboring atoms after Cu doping in SrTi〈em〉O〈/em〉〈sub〉3〈/sub〉 are observed. Furthermore, the partial density of states of SrTiO〈sub〉3〈/sub〉 changes significantly at the bottom of conduction band and hence we conclude that the Cu doping affects the electronic band structure of SrTi〈em〉O〈/em〉〈sub〉3〈/sub〉. Cu doped SrTi〈em〉O〈/em〉〈sub〉3〈/sub〉 offers enhanced optical properties and its conversion to direct band gap makes it an appealing candidate for optoelectronic devices.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Adel M. Mohammedein, Adel A. Ghoneim, Ashraf H. El-Essawy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, the interaction effect on the magnetic properties of synthetically charged boson atoms in 2D deep optical lattice are investigated. The analysis was made using the methodology of Hartree-Fock approximation for which an integral over phase-space is performed to calculate the accurate grand canonical thermo-magnetic potential. Subsequently, the grand potential is used to determine magnetic susceptibility, magnetization as well as the heat capacity at fixed magnetic field. Our approach provides a new approach to use optical potential to reach highly strong synthetic magnetic field. The outcome results provide a theoretical viewpoint for the experiment carried out by Bloch and his coworker.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Liang Wang, Jinfei Liu, Tang Tang, Nan Xie, Fanghong Sun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Boron doped, silicon doped and nitrogen doped diamond films with different doping level in gas phase are deposited on Co-cemented tungsten carbide (WC-Co) inserts using hot filament chemical vapor deposition (HFCVD) method. Trimethyl borate ((CH〈sub〉3〈/sub〉O)〈sub〉3〈/sub〉B), tetraethoxysilane (Si(OC〈sub〉2〈/sub〉H〈sub〉5〈/sub〉)〈sub〉4〈/sub〉) and urea (CO(NH〈sub〉2〈/sub〉)〈sub〉2〈/sub〉) are dissolved in acetone to serve as boron, silicon and nitrogen precursors, respectively. The 〈em〉as〈/em〉-deposited diamond films are characterized by field emission scanning electron microscope (FESEM), Raman spectroscopy and indentation tests. The results suggested that doping source and doping level will affect the surface morphology, growth rate, quality and adhesion of diamond film. The optimized doping level to obtain diamond films deposited on WC-Co substrate for mechanical applications with well faceted crystal, low defect, low cluster structure and high adhesive strength is 5000 ppm, 10000 ppm and 10000 ppm for boron, silicon and nitrogen doping, respectively.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Liqiang Li, Wenxing Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A series of copper sulfide (Cu〈sub〉7〈/sub〉S〈sub〉4〈/sub〉) nanowire arrays were prepared via a solid–gas reaction on Si and indium tin oxide (ITO)-coated glass substrates. The characterization of the Cu〈sub〉7〈/sub〉S〈sub〉4〈/sub〉 nanowire arrays was performed using scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and diffuse reflectance spectroscopy. The nanowires on the Si wafer were orthorhombic and monoclinic Cu〈sub〉7〈/sub〉S〈sub〉4,〈/sub〉 which were thin and straight, whereas the nanowires on ITO-coated glass were monoclinic Cu〈sub〉7〈/sub〉S〈sub〉4〈/sub〉, had a bigger diameter, and were bent. Although the average light absorption of Cu〈sub〉7〈/sub〉S〈sub〉4〈/sub〉 nanowire arrays on Si and ITO-coated glass substrates is lower than that of the Cu〈sub〉2〈/sub〉S nanowire arrays grown directly on Cu foil, the light absorption of the nanowire arrays on the Si and ITO-coated glass substrates remains high (59% and 84%, respectively) across a wide range of wavelengths. The light absorption and composition of the nanowire arrays can be adjusted by changing the thickness of the precursor Cu film. Our results demonstrate that copper sulfide nanowire arrays could potentially be applied in photovoltaics.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Majid Mahmood, Muhammad Asif Yousuf, Mirza Mahmood Baig, Muhammad Imran, Muhammad Suleman, Muhammad Shahid, Muhammad Azhar Khan, Muhammad Farooq Warsi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work erbium (Er〈sup〉3+〈/sup〉) substituted cobalt zinc ferrite having general formula Co〈sub〉0.70〈/sub〉Zn〈sub〉0.30〈/sub〉Er〈sub〉x〈/sub〉Fe〈sub〉2-x〈/sub〉O〈sub〉4〈/sub〉 (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) were fabricated using micro-emulsion technique. The substitution of Er was done for the purpose of tuning the optical band gap. Er〈sup〉+3〈/sup〉 substituted nanoparticles were annealed at 700 °C for 7 h. A typical composition of Co〈sub〉0.70〈/sub〉Zn〈sub〉0.30〈/sub〉Er〈sub〉x〈/sub〉Fe〈sub〉2-x〈/sub〉O〈sub〉4〈/sub〉 was utilized to make the nanocomposites material with reduced graphene oxide (rGO), that was prepared by facile chemical route. The main purpose of graphene was to enhance the conductivity of ferrite particles. All these ferrite particles and a composite were characterized by X-rays diffraction (XRD), UV–Visible spectroscopy and SEM for structural elucidation and morphology studies. Single phase spinel structure was confirmed by XRD analysis and crystallized size calculated by Scherer formula was found in the range 35–60 nm. SEM confirmed the well dispersed ferrite particles among graphene sheets. All the Er-substituted ferrite particles were subjected to dielectric parameters study. One typical composition of Co〈sub〉0.70〈/sub〉Zn〈sub〉0.30〈/sub〉Er〈sub〉x〈/sub〉Fe〈sub〉2-x〈/sub〉O〈sub〉4〈/sub〉 particles and its composites with rGO were utilized for photocatalysis study using methylene blue as model organic compound in the presence of visible light. Current-voltage (I-V) measurements of ferrites nanoparticles and their composites with graphene were also studied. The results of all these techniques were agreed with each other and suggested the various potential applications of these nanoparticles.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): Harun Güney, Demet İskenderoğlu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, undoped and 0.3%, 1.7% and 4.5% Zn doped CdO thin films were grown by successive ionic layer adsorption and reaction (SILAR) method on the soda lime glass substrate at room temperature. X-ray diffractometer (XRD), ultraviolet–visible spectrometer, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Raman and Photoluminescence (PL) spectrometer measurements of the samples were taken to observe how the Zn doping effects on the structural, optical and morphological properties of CdO. XRD measurements show that the samples have the cubic structure. It was observed that calculated by the absorption measurements band gaps varied from 1.62 eV to 2.66 eV with changing Zn dopant in the CdO structure. It was observed that the samples surface morphologies were affected by Zn-doping and its rate. The Raman spectra of undoped and Zn doped CdO thin films were observed that 288 cm〈sup〉−1〈/sup〉, 557 cm〈sup〉−1〈/sup〉, 937 cm〈sup〉−1〈/sup〉. The PL spectrum showed that the PL intensity increases with Zn doping in CdO. The PL spectra showed that Zn ions were located in the structure of CdO.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): R.I. Alekberov, A.I. Isayev, S.I. Mekhtiyeva, M. Fábián〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The partial, total and average coordination number of atoms and, their neighbor distributions have been determined by the neutron diffraction method and application of the Reverse Monte Carlo modeling for experimental data in As〈sub〉40〈/sub〉Se〈sub〉60〈/sub〉, As〈sub〉40〈/sub〉Se〈sub〉30〈/sub〉S〈sub〉30〈/sub〉 and As〈sub〉40〈/sub〉Se〈sub〉30〈/sub〉Te〈sub〉30〈/sub〉 chalcogenide glasses. The total coordination number of the arsenic and chalcogen atoms is 3 and 2 for all compounds. The average coordination number is 2.4, i.e. the 8-N rule is performed and main structural element is AsSe〈sub〉3〈/sub〉 type pyramids, where depending on the chemical composition Se atom is replaced by S or Te atoms. The proportion of homopolar bonds is significant in As〈sub〉40〈/sub〉Se〈sub〉60〈/sub〉 and As〈sub〉40〈/sub〉Se〈sub〉30〈/sub〉S〈sub〉30〈/sub〉 compositions, but sharply decreases in As〈sub〉40〈/sub〉Se〈sub〉30〈/sub〉Te〈sub〉30〈/sub〉. In all compositions the neighbor distances between arsenic and selenium atoms are the same within error: 2.35 Å (Se〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Se); 2.45 Å (As〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉As) and 2.40 Å (As〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Se). The existence of medium range order (MRO) is proved by the analysis of the total and partial pair structural factors and correlation functions in above mentioned compositions. The geometric dimensions of the MRO area, i.e. the quasi-periodicity of density fluctuations in the MRO area and the size of nano-voids have determined within Elliott's void-based model. The change of the optical parameters by variation of the chemical composition has been established from the analysis of the optical transmission spectra.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 553〈/p〉 〈p〉Author(s): Abdelghani Khaldi, Nadir Bouarissa, Hatem Ghodbane, Laurent Tabourot〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We investigate the structural phase transition, elastic constants and their related mechanical properties, stability and optical response of zinc-blende MnSe by the pseudopotential plane-wave method within the generalized gradient approximation using different parameterizations. At zero pressure, our findings show generally a reasonably good accord with available data reported in the literature. Nevertheless, in most cases, our results are predictions. The transition pressure from zinc-blende phase to NaCl phase is found to occur at pressure of 1 GPa. The mechanical stability criteria are fulfilled for all pressures being considered in the present work. All features of interest are affected by the presence of pressure leading to new physical properties of the material in question.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Ayman M. Abdalla, Atif M. Ali, M. Al-Jarallah〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, pure and transition-metal (silver (Ag)) activated zinc sulfide (ZnS) nanoparticles were prepared using a hydrothermal technique. The particles have spherical shape. The average crystallite size value of ZnS:Ag nanoparticles estimated from the XRD patterns is 4.2 nm. Our results also show that the prepared ZnS has a zinc blende structure. An absorption peak at 350 nm was observed from UV–Vis spectrum for 0.05 mol% Ag doped ZnS which is related to the cubic phase of bulk ZnS. A typical Raman peak of ZnS:Ag crystal at around 346 cm〈sup〉−1〈/sup〉 is detected. An optimum activating level of Ag for improved photoluminescence (PL) property is found by measuring the fluorescence of samples. The PL spectra of ZnS:Ag nanoparticles showed a new PL band at 473 nm. Results of ZnS:Ag nanoparticles preparation and optimization, along with structural and optical estimation are discussed and addressed thoroughly. A linear relationship between PMT counts and the flounces of alpha particles has been achieved. The detection efficiency of Lucas cell coated with the prepared samples has been determined.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Sachin Jaidka, Savidh Khan, K. Singh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the present study, Na〈sub〉2〈/sub〉O doped CeO〈sub〉2〈/sub〉 has been prepared by solid state reaction method. The prepared samples are characterized by X-ray diffraction (XRD), UV–Visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscope (SEM) and Impedance spectroscopy. The optical band gap of all the samples lies in the semiconducting range i.e. 3.04–3.25 eV. The highest optical band gap is observed for 5 mol% Na〈sub〉2〈/sub〉O doped CeO〈sub〉2〈/sub〉. The SEM images show a non-uniform distribution of particles with an average particle size of ∼3.15 μm for all the samples. The lowest dielectric constant is observed to be ∼11 at 100 °C and 100 Hz for 10 mol% doped CeO〈sub〉2〈/sub〉 which is lower than the undoped CeO〈sub〉2〈/sub〉. The conductivity of the samples lies in the range of 10〈sup〉−7〈/sup〉 S/cm at 700 °C.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): Xiao-Xiao Song, Yao Wang, Song Li, Chuan-Lei Jia〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The planar waveguides have been fabricated in Nd:YLF crystals by Si implantation. The guiding properties of Si-implanted waveguide are evaluated by the prism-coupling technique and reflectivity calculation method (RCM), exhibiting good confinement and monomode behavior at 632.8 nm. The investigation of the photoluminescence (PL) measurement demonstrates that the luminescence characteristics of the Nd〈sup〉3+〈/sup〉 ions are not significantly altered by the Si ions irradiation process, whereas the up-conversion (UC) luminescence intensity can be effectively improved. Based on the pump-power-dependent fluorescence, the possible emission mechanism in Nd:YLF is proposed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Fatemeh Saeb, Mohammad Eatesami〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bose correlations (BC) and pairing associations (PA) are known as two distinct origins for condensation. For most known condensates, condensation is only attributed to one of them. Recent developments call for research on combining the roles of the two origins. Therefore, we investigate the pairing and condensation in a boson-like system through a quantum microscopic approach based on correlation functions and order parameter equation (OPE). For the first time, we obtain general expressions for complex optical conductivity of such condensates. We focus on an interesting self-consistent solution of the OPE, i.e. a condensate with spherically symmetric order parameter growing linearly up to a radius in the momentum-space, and extract interesting predictions for it. The appearance of a temperature dependent energy gap in the middle of excitation spectrum and the appearance of a pseudogap in the absorption spectrum (without a counterpart in the excitation spectrum) in addition to the possibility of condensation at room temperature are among our predictions. Also, the paper provides several coherent pieces of evidence for the interest: the roles of BC and PA combine for creating a novel superconductor similar to MgB〈sub〉2〈/sub〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Ramesh Chandra Bhatt, S.O. Manjunatha, Ashok Rao, Riya Thomas, V.P.S. Awana, C.F. Lin, Y.K. Kuo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A systematic study on the thermal conductivity, Seebeck coefficient and specific heat of La〈sub〉0.7〈/sub〉Ca〈sub〉0.2〈/sub〉Sr〈sub〉0.1〈/sub〉MnO〈sub〉3〈/sub〉:PdO composites is presented. Solid state reaction procedure was employed to synthesis the samples. It is seen from thermal conductivity (〈em〉κ(T)〈/em〉) studies that the samples exhibit a slope change nature close to their corresponding magnetic phase transition temperature, 〈em〉T〈/em〉〈sub〉〈em〉C〈/em〉〈/sub〉. The overall magnitude of 〈em〉κ〈/em〉 is observed to decrease with increasing Pd concentration. The analysis of Seebeck coefficient data, 〈em〉S(T)〈/em〉 versus temperature, 〈em〉T〈/em〉 was done using Mott's polaron hopping model reveals that the electron-magnon scattering is governing the low temperature region. The temperature dependent specific heat 〈em〉C〈/em〉〈sub〉〈em〉P〈/em〉〈/sub〉〈em〉(T)〈/em〉 is analyzed to determine the entropy change (Δ〈em〉S〈/em〉) during the magnetic phase transition.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): Mohammed A. Assiri, M. Aslam Manthrammel, A.M. Aboraia, I.S. Yahia, H.Y. Zahran, V. Ganesh, Mohd Shkir, S. AlFaify, Alexander V. Soldatov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, nanostructured methyl violet-10B (MV-10B) thin films of various thicknesses were coated on glass substrates by a low-cost spin coating method at different rpm. The structural analysis of nanostructured MV-10B thin films was carried out by X-ray diffraction and atomic force microscope. Optical measurements were carried out, and the direct band gap of MV-10B films was estimated. The study showed that the prepared MV-10B thin films act in the same manner as that of conventional direct bandgap semiconductors. From optical studies, the sample exhibited bandpass filter characteristics in IR range from 700 nm to 900 nm and in the visible range centered around 408 nm. Also, the sample absorbs or attenuates the range of wavelengths in the visible spectrum between 470 and 650 nm creating a good absorption band valley making a CUT-OFF laser filter. Optical constants such as refractive index (〈em〉n〈/em〉) and extinction coefficient (〈em〉k〈/em〉) were computed using Kramers–Kronig relations. The real and imaginary components of dielectric constant were calculated on the basis of polarization of light when it is impinging on semiconductors. Nonlinear index of refraction and susceptibilities were estimated by linear refractive index dispersion principles. Optical limiting studies showed that the MV-10B thin films are very good optical limiters even at low thickness. The MV-10B showed a laser attenuation behavior for He-Ne and green lasers. The obtained results suggest that the newly designed thin films are the promising candidate in different applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): S. Cetinkaya Colak〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A 60% SiO〈sub〉2〈/sub〉-20% Na〈sub〉2〈/sub〉O-18% CaO-2% Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 glass structure was prepared and 20 wt% CoO was incorporated to this base glass to produce black glass by melt-quench technique. The effects of transition metal ions on the physical, thermal and optical properties of the black glass were investigated as V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 and CuO were doped to its structure. The density values of the glasses range from 2.59 g cm〈sup〉−3〈/sup〉 to 2.89 g cm〈sup〉−3〈/sup〉. As the doping ratio of transition metal ions increased, the glass transition temperature (T〈sub〉g〈/sub〉) values increased but the melting temperatures (T〈sub〉m〈/sub〉) did not show this regular change. The thermal stability and glass forming ability values of all glasses were also calculated. The absorption spectra of glasses were taken in the wavelength range 200–1100 nm. The values of optical band gap energy were determined from Mott and Davis's model. The refractive index values were calculated with the help of the optical band gap results by use of the Dimitrov-Sakka relation. Optical dielectric constants were also calculated by using the refractive index values. All results were elucidated with regard to the structural changes obtained effect of the transition metal ions. The variation in physical, thermal and optical properties was related to the non-bridging oxygen change in the structure.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 7 September 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): Dongjin Choi, Jumi Lee, Minh Dinh Phan, Kwang Pyo Hong, Kwanwoo Shin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A horizontal neutron reflectometer, Bio-REF, which is dedicated to the structural characterization of polymer and biological thin films and multilayers, has been commissioned at the 30 MW HANARO cold neutron reactor in Korea. The Bio-REF is a hybrid of horizontal and vertical scattering geometries, in which the sample is placed horizontally, and the specular reflectivity is mainly measured by the tilt of sample stage and a wide-range translating detector in θ ‒ 2θ mode. While the horizontal sample setup makes the instrument possible to conduct the measurements on a “free-liquid” system as well as mounting sophisticated sample environments, the θ ‒ 2θ operation allows to maintain the incident beam intensity and, together with the wide translational-length of the detector, the instrument is, therefore, capable of reaching a high 〈em〉Q〈/em〉 ∼0.5 Å〈sup〉−1〈/sup〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Shama Parveen, Avshish Kumar, Samina Husain, Mohammad Zulfequar, Mushahid Husain〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The authors in this research investigated the role of double catalyst layer Fe/Al in the growth of SWCNTs to obtain high current density, low turn on field and high field enhancement factor to act as efficient field emitters. We synthesise SWCNTs by PECVD technique using Fe/Al as a dual catalyst layer on Si substrate. It is seen that during the growth of SWCNTs, Al act as a barrier layer which reduces the diffusion of Fe catalyst in Si substrate resulting in high density vertically aligned growth of SWCNTs. Field emission measurements show high current density 30.5 mA/cm〈sup〉2〈/sup〉 at very low turn-on field 1.2 Vμm〈sup〉−1〈/sup〉 with a high field enhancement factor of 1.6 × 10〈sup〉4〈/sup〉. Stability and repeatability parameters of as-grown highly vertically aligned SWCNTs are also studied as a function of current density. Stability results show fairly stable field emitters for 7 h with good repeatability.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Marwen Hannachi, Wajdi Belkacem, Martiane Cabié, Rachid Belhi, Najeh Mliki〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Au/Co/SmCo/Au films with different SmCo and Co thickness were grown on silicon (100) substrates by electron-beam evaporation. The morphology of these films has been analyzed by transmission electron microscopy. The magnetic properties of the bilayers were investigated by magneto-optical Kerr effect. Hysteresis loops show a SmCo/Co single-phase behavior indicating a strong exchange coupling between the soft and hard phases. Also, we have shown that the magnetization reversal dynamics is dominated by domain wall motion.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Takayuki Yanagida, Hiroyuki Fukushima, Go Okada, Noriaki Kawaguchi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Eu:BaFBr is typically used in a ceramic form for imaging plate, and it has not been commonly studied in a single crystal form and for scintillator applications. In this study, we prepared Eu:BaFBr single crystal by the Bridgeman method and then evaluated the scintillation properties. The crystal showed an intense scintillation emission spectrum under X-ray excitation with a peak appeared at 395 nm due to the 5d-4f transitions of divalent Eu ion, and the scintillation decay time under X-ray irradiation was 1.4 μs. When we irradiated with γ-rays by 〈sup〉137〈/sup〉Cs, a clear photoabsorption peak was observed in the pulse height spectrum, and the scintillation light yield was estimated to be 27000 ph/MeV. By using various radio isotopes, we investigated the relation between peak channels of photoabsorption peak and γ-ray energy, and we confirmed a linear relationship from 60 keV to 1.27 MeV. To the best of our knowledge, this is the first report of Eu:BaFBr crystal demonstrating as a scintillator for γ-ray detections.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Ali Olad, Sahar Shakoori, Sajedeh Mohammadi Aref〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present study reports the electrical characteristics of a low voltage ZnO/Polypyrrole nanocomposite varistor which was fabricated as a thin disk based on zinc oxide with different weight percentages of polypyrrole as additive using a cold pressing method. Current-voltage characteristics and nonlinear coefficients of the ZnO/Polypyrrole nanocomposite thin disks were studied in direct current mode. Results showed good varistor behavior of prepared ZnO/Polypyrrole nanocomposite. According to the results, ZnO/Polypyrrole nanocomposite thin disk varistors can be utilized to preserve circuits from 35 V up to 350 V over voltages. I-V characteristics of nanocomposite samples showed that by increasing zinc oxide content from 98.52% to 99.01%, the breakdown voltage of ZnO/Polypyrrole nanocomposite varistor increased whereas its nonlinear coefficient decreased. However, more increase in ZnO content of nanocomposite caused to the reduction of its breakdown voltage and increase of nonlinear coefficient. The results obtained from SEM micrographs indicated that by increasing ZnO content, both the grain numbers and their morphologies are changed which is caused the different effects in the grain boundaries, I-V characteristics, and varistor properties of nanocomposites. As a very important result, in this experimental work, an ideal varistor with sufficient low breakdown voltage and acceptable high nonlinear coefficient was obtained.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): Ekaterina S. Nikova, Yuri A. Salamatov, Evgeny A. Kravtsov, Viktor I. Bodnarchuk, Vladimir V. Ustinov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The experimental phase determination in neutron reflectometry with gadolinium reference layer demands precise values of the parameters of reference layer including its scattering characteristics. It is especially important for time-of-flight experiments since in this case one must know these characteristics at each reflectivity point. So it is desirable to specify the reference layer scattering parameters directly during the experiment. In this work the way for determination of scattering characteristics, using the neutron absorption measurements on a thin film sample, is presented.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Xiaotong Zhang, Junchao Liu, Yuejia Liu, Ge Sang, Tao Gao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The structural, electronic, dynamic and thermodynamic properties of Zr〈sub〉1-〈em〉x〈/em〉〈/sub〉Hf〈sub〉〈em〉x〈/em〉〈/sub〉H〈sub〉2〈/sub〉 (where 〈em〉x〈/em〉 is the concentration of constituent element Hf, which changes in the range from 0 to 1 with step size Δ〈em〉x〈/em〉 = 0.1) are investigated using first-principle calculations. These are done using the density-functional theory (DFT) and density functional perturbation theory (DFPT) within Generalized Gradient Approximation (GGA) and employing virtual-crystal approximation (VCA) method. The lattice constant gradually decreases from 3.527 Å to 3.474 Å with Hf substitute ratio increasing and the variation is quite small. The electronic density of states (DOS) of Zr〈sub〉1-〈em〉x〈/em〉〈/sub〉Hf〈sub〉〈em〉x〈/em〉〈/sub〉H〈sub〉2〈/sub〉 gradually expands when 〈em〉x〈/em〉 value varies from 0 to 1 and all of these compounds show metallic nature and the metallicity increases. The analyses of charge density and the charge density differences indicate that the Zr〈sub〉1-〈em〉x〈/em〉〈/sub〉Hf〈sub〉〈em〉x〈/em〉〈/sub〉-H interactions in the hydride are primarily metallic with a small ionic component, and the metallic nature enhances as 〈em〉x〈/em〉 increases. Moreover, with Hf substitute ratio increasing, the optical branch and the acoustical branch of the phonon spectrum have a larger separation, which grows from 23.24 THz (ZrH〈sub〉2〈/sub〉) to 25.48 THz (HfH〈sub〉2〈/sub〉), and the phonon density of states gets wider. The calculated thermodynamic properties indicate stronger thermodynamic stability of ZrH〈sub〉2〈/sub〉 than HfH〈sub〉2〈/sub〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Keisuke T. Matsumoto, Naoya Morioka, Koichi Hiraoka〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The specific heat 〈em〉C〈/em〉 and the magnetization of Gd〈sub〉1−〈em〉x〈/em〉〈/sub〉Er〈sub〉〈em〉x〈/em〉〈/sub〉Ge〈sub〉1.5〈/sub〉 were studied. From magnetization measurements, GdGe〈sub〉1.5〈/sub〉 and ErGe〈sub〉1.5〈/sub〉 showed antiferromagnetic ordering at the N〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mover accent="true"〉〈mrow〉〈mi mathvariant="normal"〉e〈/mi〉〈/mrow〉〈mo〉́〈/mo〉〈/mover〉〈/mrow〉〈/math〉el temperatures 〈em〉T〈/em〉〈sub〉N〈/sub〉 of 29 K and 3 K, respectively. The jump in the 〈em〉C〈/em〉 of Gd〈sub〉1−〈em〉x〈/em〉〈/sub〉Er〈sub〉〈em〉x〈/em〉〈/sub〉Ge〈sub〉1.5〈/sub〉 due to the antiferromagnetic transition became small with increasing Er content, which is originated from the crystalline electric field effect and atomic randomness. Plots of 〈em〉C〈/em〉 as a function of temperature for Gd〈sub〉1−〈em〉x〈/em〉〈/sub〉Er〈sub〉〈em〉x〈/em〉〈/sub〉Ge〈sub〉1.5〈/sub〉 with 〈em〉x〈/em〉 ≥ 0.5 exhibited a peak at temperatures below 15 K. These results suggest that 〈em〉T〈/em〉〈sub〉N〈/sub〉 could be controlled by substituting Er for Gd.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Prashant Shukla, Shristi Tiwari, Shalik Ram Joshi, V.R. Akshay, M. Vasundhara, Shikha Varma, Jai Singh, Anupama Chanda〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper reports the structural, morphological and optical properties of undoped and cobalt doped (1, 10 atomic wt% Co) ZnO thin films on glass substrates prepared by a simple cost effective sol-gel spin coating technique. The effect of cobalt doping on the optical properties like transmittance, refractive index, extinction coefficient, etc. was investigated. X-ray diffraction (XRD) and Raman spectra confirm the formation of wurtzite ZnO structure with (100) as the preferred orientation. Atomic force microscopy (AFM) images of ZnO and Co-doped ZnO films show smooth surfaces with a uniform distribution of spherical grains on the surface. The morphological changes from undoped to doped samples are more evident from the correlation images obtained using MATLAB software. All the films show more than 80% of transparency in the entire visible region while 10% Co-doped ZnO film has the highest transparency (〉94%). Spectroscopic ellipsometry was used to study the refractive index and extinction coefficient which indicates the highest refractive index and lower extinction coefficient for 10% Co-doped ZnO thin films. High transparency in the visible region along with a high refractive index and lower extinction coefficient in Co-doped ZnO films can be useful for optoelectronic devices.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): H. Sadou, T. Hacib, Y. Le Bihan, O. Meyer, H. Acikgoz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, the microwave characterization of dielectric materials using open-ended coaxial line probe is proposed. The measuring cell is a coaxial waveguide terminated by a dielectric sample. The study consists in extracting the real and imaginary part of the relative dielectric permittivity (ε = 〈em〉ε′〈/em〉-〈em〉jε''〈/em〉) of the material under test from the measurements of the probe admittance (〈em〉Y〈/em〉〈sub〉mes〈/sub〉(〈em〉f〈/em〉) = 〈em〉G〈/em〉〈sub〉me〈em〉s〈/em〉〈/sub〉(〈em〉f〈/em〉)+〈em〉jB〈/em〉〈sub〉mes〈/sub〉(〈em〉f〈/em〉)) on a broad band frequency (〈em〉f〈/em〉 between 1 MHz and 1.8 GHz), hence a direct and inverse problems have to be solved. In order to build a database, the direct problem is solved using Finite Elements Method (FEM) for the probe admittance (〈em〉Y〈/em〉(〈em〉f〈/em〉) = 〈em〉G〈/em〉(〈em〉f〈/em〉)+〈em〉jB〈/em〉(〈em〉f〈/em〉)). Concerning the inverse problem, Partial Least Square (PLS) Regression (PLSR) is investigated as a fast, simple and accurate inversion tool. It is a dimensionality reduction method which aims to model the relationship between the matrix of independent variables (predictors) 〈strong〉〈em〉X〈/em〉〈/strong〉 and the matrix of dependant variables (response) 〈strong〉〈em〉Y〈/em〉〈/strong〉. The purpose of PLS is to find the Latent Variables (LV) having the higher ability of prediction by projecting original predictors into a new space of reduced dimension. The original inverse model has only three predictors (〈em〉f〈/em〉, 〈em〉G〈/em〉 and 〈em〉B〈/em〉) but is nonlinear, so inspired by the extended 〈strong〉〈em〉X〈/em〉〈/strong〉 bloc method, more predictors have been created mathematically from the original ones (for example: 1〈em〉/f〈/em〉〈sup〉2〈/sup〉, 〈em〉B〈/em〉/〈em〉f〈/em〉〈sup〉2〈/sup〉, 〈em〉GB〈/em〉, 1/B, 〈em〉G〈/em〉/〈em〉f〈/em〉, 〈em〉f〈/em〉〈sup〉2〈/sup〉〈em〉G〈/em〉, 〈em〉fG〈/em〉〈sup〉2〈/sup〉〈em〉B〈/em〉, 〈em〉f〈/em〉〈sup〉2〈/sup〉〈em〉G〈/em〉〈sup〉2〈/sup〉〈em〉B〈/em〉〈sup〉2〈/sup〉, … etc) in order to take into account the nonlinearity, whence the appellation Predictors Generation Partial Least Square Regression (PG-PLSR). Inversion results of experimental measurements for liquid (ethanol, water) and solid (PEEK (Polyether-ether-ketone)) samples have proved the applicability and efficiency of PG-PLSR in microwave characterization. Moreover, the comparison study in the last section has proved the superiority of PG-PLSR on Multi-Layer Perceptron Neural Network (MLP-NN) in terms of rapidity, simplicity and accuracy.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 553〈/p〉 〈p〉Author(s): Ibrahim Nazem Qader, Mediha Kök, Fethi Dağdelen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A quaternary Cu〈sub〉80〈/sub〉Al〈sub〉13〈/sub〉Ni〈sub〉3〈/sub〉Hf〈sub〉4〈/sub〉 (wt%) shape memory alloy has been produced from high pure metallic powder through arc-melting method. Then homogenization been performed at 1173 K for 24 h and followed by a rapid cooling to salt-iced water. As a technique, one hour heat treatment at 773 K, 873 K, 973 K, 1073 K, and 1173 K, has been done to investigate some physical and structural properties. Some relevant measurements by using DSC, XRD, EDX-SEM, and Vickers hardness devices has been accomplished. While both DSC and XRD results showed that in room temperature all specimens were in austenite phase, but increasing the temperature of heat treatment make changes in the amount of precipitations presented in SEM micro-images, and hence led to a decrease in microhardness values. The sample with 1173 K heat treatment was the more stable phase compared to the other specimens, because a minimum values was obtained in calculation of Gibbs free energy and entropy.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): Nguyen Ba Duc, Vu Quang Tho〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The thermodynamic properties and anharmonic perturbation factor of orderly doped crystals are described in terms of the cumulants in extended X-ray absorption fine structure (EXAFS) spectra. The thermodynamic parameters and cumulants are studied based on the anharmonic correlated Einstein model. We derive analytical expressions for the dispersion relation, the correlated frequency and Einstein temperature, and the EXAFS cumulants. Parameters of the Morse potential, thermal expansion coefficient due to effect of anharmonicity, anharmonic factor, the EXAFS phase including the anharmonic effects depend on doping ratio of cubic-structure crystals are considered. The derived anharmonic effective potential includes the contributions of all the nearest neighbors of the absorbing and scattering atoms to account for three-dimensional interactions and the parameters of the Morse potential to describe single-pair atomic interactions. Numerical results for face-centered cubic (fcc) crystals of copper (Cu〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Cu) and silver (Ag〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Ag) and their compound Ag〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Cu agree reasonably with experiments and other theories.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Gnana Praveena Nethala, Ravindar Tadi, Ganapathi Rao Gajula, K.N. Chidambara Kumar, V. Veeraiah〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, we have studied the influence of Ce〈sup〉3+〈/sup〉on the structural, magnetic and Mossbauer properties of Sr〈sub〉1-〈/sub〉〈sub〉〈em〉x〈/em〉〈/sub〉Ce〈sub〉〈em〉x〈/em〉〈/sub〉Fe〈sub〉12〈/sub〉O〈sub〉19〈/sub〉 (〈em〉x〈/em〉 = 0.0, 0.05, 0.1, 0.15, 0.2 and 0.25). We have synthesized Sr〈sub〉1- x〈/sub〉Ce〈sub〉x〈/sub〉Fe〈sub〉12〈/sub〉O〈sub〉19〈/sub〉 using the sol – gel technique. We have investigated the structural and magnetic properties of the grown samples using X-ray diffractometer and Vibrating sample magnetometer. We have used Scanning electron microscope, FTIR and Raman spectrometer to study the morphological properties. We have also focused on the Mossbauer spectroscopy analysis. The XRD studies confirm the hexagonal with M-type magnetoplumbhite structure. The SEM image confirms the coarseness in the sample with porosity which decreases with increasing Ce〈sup〉3+〈/sup〉 in SrFe〈sub〉12〈/sub〉O〈sub〉19〈/sub〉. The FTIR spectrum confirms the formation of single phase ferrite in the grown sample. Raman spectrum reveals the formation of different vibrations of Fe〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O bonds is observed at different peaks. The VSM studies confirm the hard nature of strontium ferrite as the cerium content is increased. The saturation magnetization and remnant magnetization of all doped strontium ferrite decrease as and when the cerium is increased. Mossbauer spectrum analysis reveals that the iron ions exist in Fe〈sup〉3+〈/sup〉 state. Mossbauer study confirms that all the five sextets are attributed to the Fe〈sup〉3+〈/sup〉ions. The obtained results with Ce〈sup〉3+〈/sup〉 doping of SrFe〈sub〉12〈/sub〉O〈sub〉19〈/sub〉 demonstrate the usefulness for magnetic recording and memory devices.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): N.А. Zhuk, V.P. Lutoev, V.A. Belyy, B.А. Makeev, D.S. Beznosikov, S.V. Nekipelov, M.V. Yermolina〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The methods of EPR and NEXAFS spectroscopy were employed for the study of BiNb〈sub〉1-x〈/sub〉Fe〈sub〉x〈/sub〉O〈sub〉4-δ〈/sub〉 solid solutions of triclinic and orthorhombic modifications. The analysis of the NEXAFS Fe2p-spectra of iron oxides and the iron-containing solid solutions revealed that Fe atoms were mainly in an oxidation state of +3. In the EPR spectra of the BiNb〈sub〉1-x〈/sub〉Fe〈sub〉x〈/sub〉O〈sub〉4-δ〈/sub〉 samples of orthorhombic modification, a broad line with the center at g of 2.16–2.37 was registered along with the low-intensity signal with a g-factor of ∼4.3 observed on its low-field wing. EPR spectra of the triclinic structure samples exhibited a complex system of lines in the range of 80–300 mT. An intense complex line having features at g of 4.74–4.80, 4.04–4.10 and 3.76–3.80 was recognized in the low-field signal. The low-field wing of the line was complicated by a shoulder with g of 5.3 and by a line in the form of an absorption signal with g of 7.7–8.0. As a result of the modeling of EPR spectra, the spin-Hamiltonian parameters of Fe(III) in the structure of BiNb〈sub〉1-x〈/sub〉Fe〈sub〉x〈/sub〉O〈sub〉4-δ〈/sub〉 of triclinic modification were obtained.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): Diyou Jiang, Qing Zhou, Wenhua Liu, Tao Wang, Jianfeng Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effect of V alloying on the mechanical properties of W-V alloys was investigated by first principles calculation. First of all, we investigated the cell volumes, lattice constants and formation energies of W〈sub〉1-〈em〉x〈/em〉〈/sub〉V〈sub〉〈em〉x〈/em〉〈/sub〉 (〈em〉x〈/em〉 = 0, 0.0625, 0.125, 0.25, 0.5, 0.75, 0.875, 0.9375 and 1) alloys. Results show that W-V alloys remains 〈em〉bcc〈/em〉 structures, and it is an infinite solid solution based on V alloying in the 〈em〉bcc〈/em〉 W lattice. These structures of all W-V alloys are thermodynamically stable. Based on the optimized atomic lattices, we investigated the elastic constants of binary W-V alloys. Then we derived the elastic modulus and other related mechanical parameters according to the formulas. It is shown that the mechanical strength of W-V alloys decreases with the increases of V atom concentration. However, the mechanical strength of all alloys is higher than that of pure V metal. On the other hand, the ductility of pure W metal can be improved effectively by V alloying W metal.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): H. Rahimi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the terahertz frequency domain, we theoretically attempt to determine some properties of kerr-type nonlinear response of a graphene-coated one-dimensional quasiperiodic structure based on Fibonacci sequence. The supposed structure is constituted by silicon dioxide and nonlinear polystyrene dielectrics where graphene sheets are located between them. The calculations are accomplished by using standard transfer matrix method. Our numerical results demonstrate that the introduction of graphene sheets in the structure has an important role in reducing bistability thresholds. It is found that for both TE and TM waves the switching-up and switching-down thresholds of bistability are reduced in comparison to without graphene case. In addition, the threshold values of TM mode are less than those of TE one. Also, by manipulating parameters such as graphene chemical potential, graphene damping constant and sequence number of structure, some other interesting features are achieved. This paper provides a way to reduce bistability thresholds which are of optical switching issues.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): Sheetal Antil, Manoj Kumar, Siddhartha Lahon, Sajjan Dahiya, Anil Ohlan, Rajesh Punia, A.S. Maan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The role of hydrostatic pressure and temperature on the optical properties of a two dimensional electron gas confined in a quantum wire having Rashba spin orbit interaction is studied in this work. The energy band gap and thus the effective mass of the charge carriers are found to have strong dependence of the hydrostatic pressure on the quantum wire and its absolute temperature. This in turn affects the linear as well as the nonlinear optical properties of the quantum wire. The external magnetic field, temperature, hydrostatic pressure and the Rashba spin orbit interaction are found to interplay in determining the linear and nonlinear absorption coefficient and refractive change in the quantum wire as a response to incident electromagnetic radiation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): Lingfeng Wang, Guoli Lei, Rong Cheng, Chong Yan, Hongliang Ge〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effect second milling time on the electromagnetic properties of MnZn ferrites has been studied up to MHz range. The average particle sizes of powder ranging from 1.49 to 1.16 μm were obtained by varying the second milling time from 72 to 324min. It is found that the total losses (P〈sub〉cv〈/sub〉) deteriorate when the second milling time over 252 min and the limit particle size is 1.21 μm. The value of initial permeability (μ〈sub〉i〈/sub〉) reduces by 20% when the particle size is 1.16 μm due to the uneven distribution of grain size, indicating that uniform microstructure demands suitable particle size. Meanwhile, the eddy current loss (P〈sub〉e〈/sub〉) and residual loss (P〈sub〉r〈/sub〉) dominate the total loss at 3 MHz playing a significant role in total losses. The hysteresis loss (P〈sub〉h〈/sub〉) and eddy current loss (P〈sub〉e〈/sub〉) deteriorate gradually at 3 MHz when the particle size is 1.21 μm at 100 °C. The residual loss increases greatly with the particle size decreasing at 3 MHz. An excellent MnZn power ferrite possessing high initial permeability (μ〈sub〉i〈/sub〉 = 887), high saturation magnetic flux density (B〈sub〉s〈/sub〉 = 531 mT) and low total losses (P〈sub〉cv〈/sub〉 = 1940 kW/m〈sup〉3〈/sup〉) at 3 MHz-50 mT is synthesized in this research.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 553〈/p〉 〈p〉Author(s): Yonghong Hu, Ting Shu, Caixia Mao, Li Xue, Zhong Yan, Yunyi Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Doping is of great importance for tuning the physical and chemical properties of new two-dimensional materials. In this work, the effects of group-VA atoms doping on the geometric structure and electronic properties of arsenene and antimonene are studied by first-principles calculations. Firstly, it's found that the substitutional doping of group-VA atom can cause obvious local lattice deformation in arsenene and antimonene crystals. Secondly, the doping of group-VA atoms leads to the decreases of band gaps in arsenene and antimonene in various doping cases. Then these results are analyzed and explained according to the variations of the electron density of states and charge density. Finally, we give the scanning tunnel microscope (STM) images of arsenene and antimonene doped by the group-VA atoms, which can provide a useful reference for the experimental researchers. Our studies yield valuable information for the applications of arsenene and antimonene in the future.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 552〈/p〉 〈p〉Author(s): M.M. Abutalib〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Polyaniline nanofibers (PANI NFs) was prepared by Interfacial and rapid-mixing polymerization Fourier transform infrared (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) were used to examine of pure nanofibers. The structural, optical, thermal, and conductivity properties of pure blend and PNCs were studied by using FTIR, XRD, SEM, UV–Vis., DTA-TGA, and Ac conductivity measurement techniques and have been prepared using the casting method. The analysis of FT-IR reflects forming hydrogen bond between the PANI and PMMA. Also it's confirmed the presence interaction between GO NPs with the functional groups of PMMA/PANI matrix. The XRD data revealed the increase of amorphous domains of nanocomposites comparing to that of the pure polymer blend. The SEM indicates the uniform distribution of GO NPs on the surface of the prepared samples. From UV. Vis showed the values of optical energy gap (direct and indirect) for pure blend and nanocomposites decreases with increasing content of GO NPs. Based on DTA and TGA data, the thermal stability of all the investigated samples were improved and the activation energies were calculated. Electrical conductivity analysis indicates that the 0.9 wt % sample have a larger conductivity compared to that of prepared samples. The increase in conductivity was mainly due to the increase in mobility of charge carrier according to free-volume model.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): T. Nurgaliev, V. Štrbík, N. Gál, Š. Chromik, M. Sojková〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The electrical transport effects in interfaces of high 〈em〉T〈/em〉〈sub〉C〈/sub〉 superconducting and ferromagnetic thin film bilayer structures (YBa〈sub〉2〈/sub〉Cu〈sub〉3〈/sub〉O〈sub〉x〈/sub〉/La〈sub〉0.67〈/sub〉Sr〈sub〉0.33〈/sub〉MnO〈sub〉3〈/sub〉 junctions with areas of ∼0.2 × 10〈sup〉−4〈/sup〉 cm〈sup〉2〈/sup〉 and ∼1.21 × 10〈sup〉−4〈/sup〉 cm〈sup〉2〈/sup〉) were investigated in view of the importance of such structures for oxide electronics and spintronics applications. In some structures the junction resistance 〈em〉R〈/em〉〈sub〉j〈/sub〉, measured by a standard four probe method at 〈em〉T〈/em〉 〈 〈em〉T〈/em〉〈sub〉C〈/sub〉, can be significantly lower (even a few orders) than the real interface resistance 〈em〉R〈/em〉〈sub〉if〈/sub〉 because of which a wrong interpretation of the last may occur. We show how to evaluate the right interface resistance and the real 〈em〉R〈/em〉〈sub〉if〈/sub〉 was determined from the measurement of 〈em〉R〈/em〉〈sub〉J〈/sub〉 for the above two junctions. An unordinary effect - a “change” of the sign of the I-V characteristics in dependence on the current 〈em〉I〈/em〉〈sub〉0〈/sub〉 flowing across the bilayer junction was observed in our experiments. We explained the essence of the effect and quantitatively described the effect using a model, proposed in the paper. The conditions for observation of a “negative” value of 〈em〉R〈/em〉〈sub〉J〈/sub〉 at 〈em〉T 〉 T〈/em〉〈sub〉C〈/sub〉 were discussed as well.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): P.H. Nam, N.X. Phuc, P.H. Linh, L.T. Lu, D.H. Manh, P.T. Phong, In-Ja Lee〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mn〈sub〉1-x〈/sub〉Zn〈sub〉x〈/sub〉Fe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 (0 ≤ 〈em〉x〈/em〉 ≤ 0.7) nanoparticles were synthesised by a hydrothermal process. X-ray diffraction patterns reveal that all samples have spinel crystalline structures. Scanning electron microscopy and X-ray diffraction patterns show that nanoparticles are near-spherical in morphology and their average size is 13–45 nm. The elemental analysis was carried out by energy dispersive X-ray analysis technique. The optical direct band gap of Mn〈sub〉1-x〈/sub〉Zn〈sub〉x〈/sub〉Fe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 nanoparticle decreases from 2.38 to 1.88 eV as the Zn content increases. Moreover, the saturation magnetisation at room temperature tends to decrease with increasing Zn content. The specific absorption rate (SAR) values were measured at a fixed frequency of 178 kHz with magnetic field amplitude of 80 Oe. The SAR initially decreases with the sample concentration and its decrease is attributed to the enhancement of dipolar interaction and agglomeration of the particles. The intrinsic loss power (ILP) value varies between 6.5 and 15 nHm〈sup〉2〈/sup〉kg〈sup〉−1〈/sup〉 in the biologically safe experimental limit of 1.13 × 10〈sup〉9〈/sup〉Am〈sup〉−1〈/sup〉s〈sup〉−1〈/sup〉. The high value of ILP makes these nanoparticles possible for potential candidates for treating magnetic hyperthermia.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Yan Yang, Wei Wang, Guo-Yong Gan, Xue-Feng Shi, Bi-Yu Tang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The structural, mechanical and electronic properties of (TaNbHfTiZr)C high entropy carbide are studied by using density functional theory in conjunction with special quasi-random structures. The proposed lattice constant difference as an empirical criterion for high entropy compounds and mixing enthalpy show the formation of (TaNbHfTiZr)C solid solution. The derived elastic stiffness constants also indicate the mechanical stability of (TaNbHfTiZr)C high entropy carbide. At zero pressure, the calculated elastic mechanics obeys the rule of mixture, whereas Vickers hardness is slightly larger than the average value of constituent binary carbides. The computed elastic parameters show that (TaNbHfTiZr)C is brittle, similar to constituent binary carbides. Under high pressure, the lattice constants decrease slightly, and mechanical properties are improved, even the brittleness-ductility transition takes place. The calculated electronic structures show that covalence in (TaNbHfTiZr)C is relatively weaker than ionic bonding. With increasing pressure, covalence in (TaNbHfTiZr)C decreases while ionicity increases. The present research will be valuable for understanding and designing of high-entropy carbides.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Wenbo Peng, Tao Pang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, Y〈sub〉2〈/sub〉Mo〈sub〉4〈/sub〉O〈sub〉15〈/sub〉:Yb〈sup〉3+〈/sup〉/Er〈sup〉3+〈/sup〉 upconversion phosphors are prepared by a co-precipitation method. In the case of 20% Yb〈sup〉3+〈/sup〉 doping, the intense green upconversion luminescence is obtained, which can be attributed to the energy transfer from Yb〈sup〉3+〈/sup〉-MoO〈sub〉4〈/sub〉〈sup〉2-〈/sup〉 dimer to Er〈sup〉3+〈/sup〉 that suppresses the multi-phonon relaxation of 〈sup〉4〈/sup〉I〈sub〉11/2〈/sub〉 to 〈sup〉4〈/sup〉I〈sub〉13/2〈/sub〉. Similar the Yb〈sup〉3+〈/sup〉 sensitization, the dimer sensitization is also dependent on the Yb〈sup〉3+〈/sup〉 concentration. When the Yb〈sup〉3+〈/sup〉 concentration exceeds 20%, the luminescence is quenched by the cross relaxation and energy migration between dimers. A method for evaluating the reliability of temperature measurement standards is reported. Moreover, in term of the reliable temperature scale, the maximum absolute sensitivity of sample doped with 20% Yb〈sup〉3+〈/sup〉 is determined to be 0.0117 K〈sup〉-1〈/sup〉. Favorable sensing ability and strong upconversion luminescence indicate that the optimum sample is potentially applicable as the optical thermometric materials.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): M. Mahdouani, S. Gardelis, R. Bourguiga〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We investigated theoretically the effect of introducing Si impurities in a single layer graphene (1LG) that had been deposited on a polar substrate on the transport properties of the graphene layer. We consider in our analysis the scattering effects due to the surface optical (SO) phonons located at the interface of the 1LG with various polar substrates such as〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mi〉S〈/mi〉〈mi〉i〈/mi〉〈mi〉C〈/mi〉〈/mrow〉〈/math〉, hexagonal 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mrow〉〈mi〉B〈/mi〉〈mi〉N〈/mi〉〈mo〉,〈/mo〉〈mi〉S〈/mi〉〈mi〉i〈/mi〉〈msub〉〈mrow〉〈mi〉O〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈mi〉a〈/mi〉〈mi〉n〈/mi〉〈mi〉d〈/mi〉〈mspace width="0.25em"〉〈/mspace〉〈mi〉H〈/mi〉〈mi〉f〈/mi〉〈msub〉〈mrow〉〈mi〉O〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉. Our results demonstrate a reduction of SO phonon-limited (SOPL) mobility, and SOPL conductivity as well as an increase of the SOPL resistivity and of the scattering rate in the presence of Si impurities in the 1LG. Further, we studied the effect of Si impurities on the electron-surface phonon interaction〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.gif" overflow="scroll"〉〈mrow〉〈mo〉.〈/mo〉〈/mrow〉〈/math〉 For our analysis we used the eigenenergies aquired from the tight-binding Hamiltonian in 1LG. Indeed the presence of the Si impurities induces a decrement in the resonant coupling between the electronic sub-levels and the surface vibration modes in monolayer graphene deposited on polar substrates. Finally, we investigated the effect of Si impurities on the Auger scattering process which affects the carriers relaxation. Our results show an enhancement of the Auger scattering rate in the case of the Si-doped 1LG compared to the undoped 1LG.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 550〈/p〉 〈p〉Author(s): Qihong Fang, Yang Chen, Jia Li, Yanbin Liu, Yong Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The microstructure and mechanical properties of high-entropy alloy (HEA) coatings by plasma cladding on Ti substrate are studied by the analysis of a series of FeCoCrNiNb〈sub〉X〈/sub〉 (X = 0.25, 0.6, 0.8) HEA coatings, to reveal the additional elemental Nb effects. The results show that the HEA coatings exhibit typical dendritic structure, and consist of BCC and FCC structures. The wear resistances of FeCoCrNiNb〈sub〉X〈/sub〉 HEA coatings increase firstly and then decrease with the increase of Nb content, agreeing with the hardness of coatings. Compared with the other HEA coatings from the previous work, the friction coefficients of the FeCoCrNiNb〈sub〉X〈/sub〉 HEA coatings are relatively lower and more stable, indicating the potential applications, such as for wear protection films of gear. The FeCoCrNiNb〈sub〉0.6〈/sub〉 HEA coating shows high hardness and good wear resistance due to the reasonable volume fraction between BCC and FCC phases. The volume fraction of BCC and FCC structures in HEA coating are predicted not only using the valence electron concentration (VEC), but also by calculating parameters of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mo〉Δ〈/mo〉〈msub〉〈mtext〉H〈/mtext〉〈mrow〉〈mtext〉mix〈/mtext〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mtext〉δ〈/mtext〉〈/math〉 depending on the mixing enthalpy and the atomic size difference.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 31 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): Susmita Nath, Subrat Kumar Barik, Sugato Hajra, R.N.P. Choudhary〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract:〈/h5〉 〈div〉〈p〉The general composition of (La〈sub〉1/2〈/sub〉Li〈sub〉1/2〈/sub〉)(Fe〈sub〉2/3〈/sub〉W〈sub〉1/3〈/sub〉)O〈sub〉3〈/sub〉 (further termed as LLFWO) bulk ceramics was prepared by a cheap ceramic technology. The thermal analysis (TGA) was used to examine the weight loss and disintegration of the ingredients or mixture. The prepared solid solution crystallizes in a stable single-phase orthorhombic structure. The complex impedance and modulus spectroscopy helped to carry out the systematic investigation of electrical behaviour present in the compound over wide temperature and frequency. The effect of combined grain and grain boundary on the capacitive and resistive properties was revealed through the help of impedance spectroscopy technique. The prepared solid solution exhibits the negative temperature coefficient (NTCR) behavior like semiconductor (i.e. rise in temperature reduces the grain resistance). The Jonscher's power law was followed by the frequency dependent AC conductivity plot. The activation energy was evaluated from temperature dependent electrical conductivity. The existence of ferromagnetism with remanent magnetization of 0.79 emu/g was revealed from the M-H curve.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 554〈/p〉 〈p〉Author(s): P. Shamba, J.C. Debnath, J.L. Wang, Q.F. Gu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High pressure x-ray diffraction studies up to 10.4 GPa were performed on the Mn〈sub〉0.94〈/sub〉Ti〈sub〉0.06〈/sub〉CoGe alloy using synchrotron radiation with a diamond anvil cell. No structural phase transitions occurred in the entire range of our measurements. Unit cell parameters were determined up to 10.4 GPa and the calculated unit cell volumes were found to be well represented by a third order Birch-Murnaghan equation of state. The bulk modulus determined from the pressure – volume data was found to be, B〈sub〉0〈/sub〉 = 231.72 ± 7.79 GPa. This study, employing high resolution synchrotron x-rays has helped clarify the behaviour of the Mn〈sub〉0.94〈/sub〉Ti〈sub〉0.06〈/sub〉CoGe alloy under high pressure.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 554〈/p〉 〈p〉Author(s): Yu Xia, Liaolin Zhang, Xiao Shen, Wei Wei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Er〈sup〉3+〈/sup〉-doped oxyfluoride germanate glass containing LaF〈sub〉3〈/sub〉 nanocrystals have been prepared via heat treatment from the precursor glass. Dynamic and static spectroscopic characteristics of IR, MIR and upconversion fluorescence of Er〈sup〉3+〈/sup〉 doped transparent oxyfluoride germanate glass ceramic were investigated. When heat treat temperature increased from 540 to 600 °C, NIR and MIR fluorescence intensity increase about 3 times, and companied with 2060 times 550 nm and 350 times 660 fluorescence enhancement. Increasing the heat treat time at 560 °C from 2 to 12 h, the NIR and MIR fluorescence intensity increased about 2.5 and 1.8 times. It was due to the part of Er〈sup〉3+〈/sup〉 ions were incorporated into LaF〈sub〉3〈/sub〉 nanocrystals, resulting in the decrease of the multi-phonon relaxation of Er〈sup〉3+〈/sup〉. According to the ratio between MIR fluorescence intensity of the heat treated glass sample to that of the untreated glass sample, the number of the Er〈sup〉3+〈/sup〉 which was incorporated into the LaF〈sub〉3〈/sub〉 nanocrystals can be quantificationally estimated. It was estimated to be 0.98%–5.8% when the heat treat temperature increased from 540 to 600 °C, and 1.21%–1.63% with increasing heat treat time from 2 to 12 h.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 554〈/p〉 〈p〉Author(s): N. Mahfoudh, K. Karoui, K. Khirouni, A. Ben Rhaiem〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The hybrid compound Dimethylammonium zincochloride [(CH〈sub〉3〈/sub〉)〈sub〉2〈/sub〉NH〈sub〉2〈/sub〉]〈sub〉2〈/sub〉ZnCl〈sub〉4〈/sub〉 is synthesized using a slow evaporation method at room temperature. It crystallizes in the monoclinic system with the P2〈sub〉1〈/sub〉/n space group. The differential scanning calorimetric shows one phase transition at 444 K. In optical studies, the analysis of the data revealed the existence of optical direct allowed transition mechanisms with the band gap energy equal to 4.26 eV. The ac electrical conductivity is investigated at the frequency and temperature range of 1 Hz–1 MHz and of 415 K–451 K respectively. The presence of the grain interior and grain boundary contributions to the electrical response in the material is clearly manifested in both of the two semicircles observed in the complex impedance. The equivalent circuit based on the Z-View-software is proposed and the conduction mechanisms are determined. Dielectric data are analyzed using complex electrical modulus M* at various temperatures.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 554〈/p〉 〈p〉Author(s): Adel Belayadi, Boualem Bourahla〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Motivated to predict the properties of new material belonging to the 7000 aluminum alloys (7000-Al-alloy), in this contribution, we develop a combined model based on the artificial neural network approaches to predict the class of the Al-alloy and compute its mechanical properties. The adopted neural model is able to predict the type of alloys whether “hard and brittle” or “hard and ductile”. The concentrations of aluminum and the various additive elements (Al, Cr, Cu, Fe, Mg, Mn, Si, Ti, Zn) are used to train the neural network model.〈/p〉 〈p〉The results show a high performance in predicting and optimizing the mechanical behavior of the 7000-Al-alloys. For a better validation of our model, the 7005 (T6), 7475 (T65), 7475 (T7351), 7005 (T53), 7075 (T6), 7175 (T66), 7075 (T76), and 7075 (O) alloys are used as testing materials to predict the hardness (H), density (D), elongation (A), compressibility modulus (B), shear modulus (G) and the ratio (B/G).〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 554〈/p〉 〈p〉Author(s): K. Chen, H. Wu, S.H. Chen, H.M. Zheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the practical applications of bulk metallic glasses (BMGs) as structural materials, they always deform under complex stress states. In this work, some single-side-notched BMG specimens with varying notch radii and geometries were fabricated, and tested under tensile loadings. The effect of complex stress fields on the accumulation of plastic energy in the notched BMG specimens was examined and discussed. The results show that the notched BMGs can dissipate more plastic energy before fracture than conventional tensile specimens which have a relatively-uniform stress distribution. To accumulate more plastic energy, it necessitates high orders of stress concentration to initiate more shear bands and appropriate distribution of complex stress fields to confine their propagations. The present findings are of significance for practical structural-applications of BMGs, where complex stress fields are usually presented.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 554〈/p〉 〈p〉Author(s): T.C. Chibueze, C.M.I. Okoye〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We have employed density functional theory (DFT) to study the structural, mechanical, electronic structure and magnetic properties of wurtzite cobalt monosulphide (w-CoS). We established that within the framework of DFT, w-CoS is most stable in the anti-ferromagnetic phase but returns a metallic state contrary to the experimental reports. The cohesive energy, formation energy and elastic properties confirm that it is mechanically stable. Employing DFT with the on-site coulomb interaction term U, we established that w-CoS is an indirect band gap semiconductor with a possible direct band gap at the high-symmetry point 〈em〉A〈/em〉 in agreement with experimental data. We also studied the dependence of magnetic moment of Co ion on the coulomb interaction term U and found that U values ranging from 5.5 eV to 8.0 eV best accounts for the wide range of the experimentally reported band gaps.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 554〈/p〉 〈p〉Author(s): Manman Liu, Lijie Zhang, Jieyuan Liang, Xiaoxiao Li, Youqing Dong, Chao Zou, Yun Yang, Keqin Yang, Shaoming Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Atomic thinness, excellent transport property and gate-tunable band structure of graphene render it a potential electrode material for assembling ultra thin electronic devices. Here, we present back gate field effect transistor based on exfoliated monolayer (ML) ReS〈sub〉2〈/sub〉 as channel semiconductor and exfoliated ML-graphene as drain-source electrodes. The G and 2D peaks of ML-graphene stiffen significantly and their intensity ratio increases as well when the graphene is encapsulated between the SiO〈sub〉2〈/sub〉/Si substrate and ReS〈sub〉2〈/sub〉. Owing to the excellent electron transport properties of the ML-ReS〈sub〉2〈/sub〉 and gate-tunable Fermi-level of the underlying ML-graphene, the transistor exhibits on/off current ratio exceeding 10〈sup〉6〈/sup〉, mobility of ∼1.1 cm〈sup〉2〈/sup〉 V〈sup〉−1〈/sup〉s〈sup〉−1〈/sup〉 and subthreshold swing ∼740 mV per decade. This work indicates that ML-graphene is an excellent electrode material for fabricating atomically thin ReS〈sub〉2〈/sub〉 electronic devices.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 10 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): H.Y. Zhang, Y.L. Yang, J.F. Pan, H. Long, L.S. Huang, X.K. Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Although surface microstructures is the key to superhydrophobicity, and possibly leads to significant icephobicity when a water droplet freezes on superhydrophobic surfaces (SHS), thermodynamic mechanisms responsible for the icephobicity and anti–icing still need to be further studied. For this reason, we established the relationships between some quantities, i.e., contact angle (CA) together hysteresis, adhesion work and the microstructures by a three–dimension (3–D) surface model, and theoretically explained the anti–icing and icephobicity from the SHS. Our theoretical and experimental study indicate, the adhesion work (〈em〉W〈/em〉〈sub〉〈em〉ai〈/em〉〈/sub〉) of a frozen water droplet to the SHS in composite wetting state (CWS) is apparently less than that in the non–composite wetting state (NCWS). Therefore it is necessary to create such CWS by designing surface micro/nanostructure. Further study also shows, the adhesion work (〈em〉W〈/em〉〈sub〉〈em〉aw〈/em〉〈/sub〉) of a water droplet to the SHS is larger than that (W〈sub〉ai〈/sub〉) of their frozen, thus implying decrease of the adhesion work after icing. This will improve on the understanding of the SHS for anti–icing and icephobicity.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Variations of the normalized adhesion works of the frozen droplet with one–dimensional solid fraction, and a comparison of the normalized adhesion work between two–step and one–step microstructures as well as composite and non–composite wetting state.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0921452618308093-fx1.jpg" width="345" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 8 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): Mohammad Riazuddin Molla, A.Z. Ziauddin Ahmed, M. Alamgir Hossain, G.M. Bhuiyan, M.M. Rahman〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A study of static and dynamic properties for liquid Fe using orbital free 〈em〉ab-initio〈/em〉 molecular dynamics (OF-AIMD) simulation technique at thermodynamic states near the melting point is presented for the first time. The OF-AIMD simulation method is related to the density functional theory. Different static magnitudes such as static structure factors, isothermal compressibility, pair distribution functions and coordination numbers obtained from simulation are described. And the dynamic properties for both single and collective dynamics such as dynamic structure factors, diffusion coefficients, adiabatic sound velocity, and shear viscosity are also reported. The evaluated results for static and dynamic properties are found to be good in agreement with the available experimental data. Most importantly, a comparison with some KS-AIMD results shows that the degree of accuracy of the present OF-AIMD study is as good as that of the KS-AIMD.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): M. Chaitanya Varma, S. Bharadwaj, K. Vijaya Babu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Anomalous variation in cation distribution in chromium doped Ni-Co-Cu-Cr ferrites synthesized by sol-gel method has been observed the formation of spinel structure and explained with the help of DTA/TG and X-ray diffraction analysis. Error estimated between theoretical and calculated lattice parameter based on proposed cation distribution is found be in range of 0.0014% to 0.00005%, which confirms the cation distribution predicted for the present samples. In this present work, it appears that most of the cobalt and 50% of nickel ions are observed to occupy A-sites instead of B-sites of spinel lattice, which is a drastic deviation from the reports published till date. The g-value have been found to be lower for x = 0.02 concentration as observed from ESR analysis. Fourier transform infrared spectroscopic techniques (FTIR) show no variation in peak position of vibrational bands, indicates the uniform bond length in the spinel ferrite, even for different concentration of chromium. This is further confirmed by the bond length calculation using empirical formulas and experimental lattice parameters, showing least error for shared and unshared ion for tetrahedral or octahedral sites.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 555〈/p〉 〈p〉Author(s): X.H. Huang, H.Y. Lin, Z.J. Cheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A softening of bending mode and a hardening of stretching mode on cooling are observed in infrared spectra of La〈sub〉0.25〈/sub〉Ca〈sub〉0.75〈/sub〉MnO〈sub〉3〈/sub〉 nanoparticles with particle sizes (〈em〉D〈/em〉) of 40–1000 nm, indicating part of melting charge ordering in the samples. The particle size variations of the inverse of effective number of carriers 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈msubsup〉〈mrow〉〈mi〉n〈/mi〉〈/mrow〉〈mrow〉〈mi〉e〈/mi〉〈mi〉f〈/mi〉〈mi〉f〈/mi〉〈/mrow〉〈mrow〉〈mo〉∗〈/mo〉〈/mrow〉〈/msubsup〉〈/mrow〉〈/math〉 and optical gap show their maxima around 〈em〉D〈/em〉 = 350 nm at 〈em〉T〈/em〉 = 6 K and then decrease as 〈em〉D〈/em〉 reduces from 350 nm to 40 nm. The signals of the decreasing localization of charge carriers provide the possible evidences for the suppression of charge ordering with the decreasing particle size. These observations are explained based on the model of disordered surface and bulk-like core.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 555〈/p〉 〈p〉Author(s): Firas J. Al-Maliki, Esraa A. Al-Oubidy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, high-quality and highly pure titanium dioxide nanostructures were synthesized by a homemade dc closed-field unbalanced reactive magnetron sputtering system. The operation parameters of the magnetron sputtering system were optimized to prepare TiO〈sub〉2〈/sub〉 nanostructures as thin films on glass substrates. These nanostructures were characterized by x-ray diffraction, atomic force microscopy and Fourier-transform infrared spectroscopy. Both anatase and rutile phases were identified. The mixing ratio of argon and oxygen (Ar:O〈sub〉2〈/sub〉) gases was found very important to control the structural characteristics of the prepared nanostructures.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 30 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): D.K. Mondal, C. Borgohain, N. Paul, J.P. Borah〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉MnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/ZnS magneto-fluorescent nanocomposite were synthesised by simple co-precipitation method and its structural, morphological, optical and magnetic characterization were done by XRD, HRTEM, FTIR and VSM techniques. The presence of MnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 and ZnS in the nanocomposites was confirmed by XRD. Magnetic study shows that the nanoparticles manifest near superparamagnetic behaviour with a small coercivity of ∼66 G at room temperature and saturation magnetization significantly increases after coating ZnS on the surface of MnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 core. The FTIR study confirms the incorporation of ZnS nanoparticles on the surface of MnFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 nanoparticles. PL spectra demonstrated the red shifted emission of nanocomposites as compared with that of pure ZnS. The heating efficiency of the nanocomposites is measured by its SAR and ILP values. This study exhibits the quantitative link between the sizes and saturation magnetization which is intimately intertwined with the heating efficiency of the nanoparticles.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 26 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): Fereshteh Salimzadeh, Saeed Rasouli Heikalabad〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Complementary Metal Oxide Semiconductor (CMOS) technology uses voltage levels for binary computation, whereas Quantum Dot-Cellular Automata (QCA) uses free electron location in the QCA cell for logic evaluation. This technology suggests very low power consumption, high speed and very dense structure for performing any logical circuit. Reversible logic is best mechanism with low power and high speed in circuit designing. Reversible gates have N input and N output lines that input lines mapped with output lines one by one. In this paper, a novel design of Reversible Full adder/subtractor with minimum number of cells has been proposed. QCADesigner software has been used to simulate the proposed design.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 21 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): Gustavo Berrío Cordero, Jean F. Murillo G, César Ortega López, Jairo Arbey Rodríguez M, Miguel J. Espitia R〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉First-principles calculations in the framework of density functional theory were carried out in order to investigate the adsorption effects of a Cr atom on the structure and electronic properties of a single ZnO monolayer with a graphene-like structure (g-ZnO). The results show that the energetically most favorable site for the adsorption of a Cr atom is T〈sub〉O〈/sub〉 (top of O atom), with an adsorption energy of -0.8475 eV. We found that the O atom that binds with the Cr atom is ejected out of the monolayer at a vertical distance of 0.4337 Å. The Cr-ZnO monolayer is characterized by a buckling structure around the O-Cr bond. The density of states calculated reveals that the Cr-ZnO monolayer exhibits a metallic behavior. The monolayer acquires magnetic properties, with a magnetic moment of 5.21 〈em〉µ〈/em〉〈sub〉〈em〉β〈/em〉〈/sub〉/cell, mainly originating from hybridization and polarization between O-p orbitals, Zn-d orbitals and Cr-d orbitals.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 14 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): Yanlian Yang, Kangxian Guo, Tao Yang, Keyin Li, Wangjian Zhai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nonlinear optical effects in semiconductor nanostructures with quantum size regime have aroused great interest due to their giant nonlinearities in contrast to those of bulk counterparts, which is of great importance for developing nonlinear optical nano-devices. Here, using quantum theory, we reveal that surface plasmon resonances of metal nanoparticles greatly enhance the linear and nonlinear optical absorption coefficients of spherical dome semiconductor nanoshells with quantum sizes. These enhanced linear and nonlinear optical effects can be flexibly tuned and amplified by manipulating both the structural parameters of the nanoshells and the distance between nanoshells and metal nanoparticles. Furthermore, the bleaching effects are more clearly observed through the surface plasmon resonances. Our founding make spherical dome semiconductor nanoshells a promising candidate for nonlinear optical nano-devices with the potential for integrated nonlinear optical applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 14 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): Akshatha Wagh, Vinod Hegde, C.S. Dwaraka Viswanath, G. Lakshminarayana, Y. Raviprakash, Sudha D. Kamath〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Authors aim to make a study on gamma (γ) rays effects over inorganic glassy materials. The Nd〈sup〉3+〈/sup〉 content as well as high energetic induced radiation in the glass compositions resulted in the B〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉B bonds depolymerization creating NBOs (Non-Bridging Oxygens) in the matrices, interpreted through FTIR (Fourier Transform Infrared) spectra. The decrease in the T〈sub〉g〈/sub〉, H〈sub〉r〈/sub〉 and H values obtained from Differential Scanning Calorimetry (DSC) thermograms and Vickers Microhardness Tester respectively, proved the changes in the glass structure after irradiation. The drastic decrease in the intensities of UV-VIS absorption and Photoluminescence (PL) emission peaks after irradiation, prompted the creation of defect points in the samples. The JO (Judd-Ofelt) theory was implemented to understand the asymmetric and covalent nature of the matrix and also to predict the radiative properties. The EPR (Electron Paramagnetic Resonance) spectra proved the presence of defects in the samples both pre and post irradiation. These changes were correlated with the Nd (Neodymium) and O (Oxygen) concentration ratios, studied through EDS (Energy-Dispersive X-ray spectroscopy), which showed decrease in the elemental composition post irradiation. The UV-VIS differential absorption spectra of the samples after γ irradiation depicts defects in the glass network with feasibility in valency change from Nd〈sup〉3+〈/sup〉 to Nd〈sup〉2+〈/sup〉 and decrease in Nd〈sup〉3+〈/sup〉 ions number density after irradiation. Dipole-Dipole interactions within the ions were analyzed through lifetime decay measurement. 1.0 mol% of Nd〈sup〉3+〈/sup〉 ions showed better radiation resistant nature and quality optical properties when compared to other samples both before and after γ rays interactions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 17 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): Mithun De, Subhash Sharma, Samar Jana〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Characteristics of absorption energy bands and luminescence emissions of 1% Eu〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 embedded in 10% PbO + 40% Na〈sub〉2〈/sub〉O + 49% P〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 glass matrix have been reported here. The absorption spectra at room temperature have been recorded in the ultraviolet-visible region. We have assigned eight energy bands which occur due to the transition from the ground multiplet 〈sup〉7〈/sup〉F〈sub〉0〈/sub〉 as well as 〈sup〉7〈/sup〉F〈sub〉1〈/sub〉. Amongst them the strongest and sharp absorption peak is noticed at 393 nm corresponding to 〈sup〉7〈/sup〉F〈sub〉0〈/sub〉 → 〈sup〉5〈/sup〉L〈sub〉6〈/sub〉 transition. The excitation spectra show that the intensity of the 〈sup〉5〈/sup〉L〈sub〉6〈/sub〉 band is the strongest. Applying excitation at 393 nm, the luminescence emissions of the Eu〈sup〉3+〈/sup〉 glass have been analyzed. Among seven emission peaks in the visible, the intense and most prominent emission is found at 612 nm in the red region due to 〈sup〉5〈/sup〉D〈sub〉0〈/sub〉→〈sup〉7〈/sup〉F〈sub〉2〈/sub〉 transition. The decay rates for this transition exhibits single exponential characteristics. The radiative parameters such as branching ratio (β〈sub〉m〈/sub〉), effective bandwidth (Δλ〈sub〉eff〈/sub〉), luminescence intensity ratio R = (〈sup〉5〈/sup〉D〈sub〉0〈/sub〉 → 〈sup〉7〈/sup〉F〈sub〉2〈/sub〉)/(〈sup〉5〈/sup〉D〈sub〉0〈/sub〉 → 〈sup〉7〈/sup〉F〈sub〉1〈/sub〉), and decay lifetime (τ〈sub〉m〈/sub〉) are measured and compared with other similar host glasses. The color chromaticity coordinates of the emission are characterized by CIE1931 (Commission Internationale de l’Eclairage) diagram. Upon excitation at 393 nm in this glass the chromaticity coordinates are estimated as (0.634, 0.346) which show red emission. It reveals high color purity of 95.3% and correlated color temperature (CCT) value of 2180 K. The result of our present work indicates that the red light emission of Eu〈sup〉3+〈/sup〉 is highly enhanced in lead sodium phosphate glass matrix in comparison to other host matrices reported in the literature.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 14 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): Yu.D. Zavorotnev, L.S. Metlov, A.Yu. Zakharov, O.Yu. Popova〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effect of temporal delay and relaxation on the structural order parameter (OP) in the course of plastic deformation by twisting is theoretically analyzed. It is shown that an anomalous behavior of the OP modulus takes place. The analysis is based on the Landau-Khalatnikov equation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 18 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): Sofia Evangelou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present results for the nonlinear optical rectification of an asymmetric GaAs/AlGaAs quantum dot structure coupled to a gold nanosphere under the influence of a strong electromagnetic field. We show that the nonlinear optical rectification coefficient depends strongly on the distance between the quantum dot and the metallic nanosphere and on the direction of the applied electromagnetic field.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter〈/p〉 〈p〉Author(s): Mehdi Zamani, Mansoureh Amanollahi, Abdesselam Hocini〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, we have theoretically investigated the optical spectra of all superconducting aperiodic photonic crystals comprising from different superconductors namely high-high, low-low and high-low temperature configurations. Also, the name Octonacci is composed of 〈em〉Octo-〈/em〉from octagonal and 〈em〉-acci〈/em〉 from the Fibonacci sequence, however, the Octonacci sequence has a geometric origin. In order to show the difference between TE- and TM-polarized lightwaves, we have analyzed both the influence of the incident angle and temperature of light wave on the PBGs as well as transmittance resonance-peaks. By the way, the possibility of obtaining deep photonic band gap (PBG) has been provided for both TE and TM polarizations for the most incident angles. This study also investigates the effect of generation number of the Octonacci sequence on the PBG spectrum within the visible range. The results show that optical performances of Octonacci all superconducting aperiodic photonic crystals are higher than Fibonacci ones even with upper generations. Finally, to show the impact of the results, we have made a comparison between this new investigating quasi-periodic sequence and periodic all superconducting ones.〈/p〉〈/div〉 〈/div〉