ALBERT

Description:    In this work, the effect of SnO 2 nano-particles (40 nm) addition to the physical properties of Bi 1.6 Pb 0.4 Sr 2 Ca 2 Cu 3 O 10+ δ superconducting phase was studied. (Bi, Pb)-2223 superconductor phase added by SnO 2 nano-particles was prepared by a conventional solid-state reaction technique. The SnO 2 nano-particles concentrations x varied from 0.0 to 2.0 wt% of the sample’s total mass. The prepared samples were investigated by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and electron dispersive spectroscopy (EDS) for analyzing phase formation and microstructure. Also, the electrical resistivity and transport critical current density, for investigated samples, were measured by standard dc four-probe method. Phase examination by XRD indicated that SnO 2 nano-particles enhanced the (Bi, Pb)-2223 phase formation up to x =0.4 wt%. On the other hand, the high concentrations of SnO 2 nano-particles retarded the phase formation. Granular investigation, from scanning electron microscope, showed that both number and size of voids decreased as x increased from 0.0 to 0.4 wt%. The superconducting transition temperature and transport critical current density were found to have optimal values at x =0.4 wt%. The enhancement rates in T c and J c were 12 and 58%, respectively, which had a maximum enhancement in both J c and T c for all investigated nano-particles. Content Type Journal Article Pages 1-8 DOI 10.1007/s10948-011-1171-z Authors A. I. Abou-Aly, Phycics Department, Faculty of Science, Alexandria University, Alexandria, 21511 Egypt M. M. H. Abdel Gawad, Physics Department, Faculty of Education, Alexandria University, Alexandria, Egypt R. Awad, Phycics Department, Faculty of Science, Alexandria University, Alexandria, 21511 Egypt I. G-Eldeen, Physics Department, Faculty of Education, Alexandria University, Alexandria, Egypt Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    It is studied within the scaling analysis the fluctuation conductivity under the magnetic fields in ReFeAsO (Re=Nd, Pr) superconductors reported in literatures. A crossover is firstly observed in these iron-based superconductors from the Lowest Landau level (LLL) regime above the magnetic field H LLL ∼6–7 T to the critical fluctuation region at the low field. The static exponent ν of ReFeAsO superconductors is estimated to be 1.85±0.05, which is close to that of Bi 2 Sr 2 CaCu 2 O 8 , and the dynamic exponent z of ReFeAsO superconductors deviates from the theoretical prediction but is similar to that extracted from the resistivity experiment using the crossing-point technique. Content Type Journal Article Pages 1-5 DOI 10.1007/s10948-011-1155-z Authors S. L. Liu, College of Science, Nanjing University of Posts and Telecommunications, Nanjing, 210003 P.R. China Yongtao Li, College of Science, Nanjing University of Posts and Telecommunications, Nanjing, 210003 P.R. China Gang Bao, College of Science, Nanjing University of Posts and Telecommunications, Nanjing, 210003 P.R. China Haiyun Wang, College of Science, Nanjing University of Posts and Telecommunications, Nanjing, 210003 P.R. China Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    The phenomenological Green’s function developed in the works of Yang, Rice, and Zhang has been very successful in understanding many of the anomalous superconducting properties of the deeply underdoped cuprates. It is based on considerations of the resonating valence bond spin liquid approximation and is designed to describe the underdoped regime of the cuprates. Here, we emphasize the region of doping, x , just below the quantum critical point at which the pseudogap develops. In addition to Luttinger hole pockets centered around the nodal direction, there are electron pockets near the antinodes which are connected to the hole pockets by gapped bridging contours. We determine the contours of nearest approach as would be measured in angular resolved photoemission experiments and emphasize signatures of the Fermi surface reconstruction from the large Fermi contour of Fermi liquid theory (which contains 1+ x hole states) to the Luttinger pocket (which contains x hole states). We find that the quasiparticle effective mass renormalization increases strongly toward the edge of the Luttinger pockets beyond which it diverges. Content Type Journal Article Pages 1-11 DOI 10.1007/s10948-011-1169-6 Authors J. P. F. LeBlanc, Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada J. P. Carbotte, Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4L8, Canada Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    We studied the possible superconducting state in an electronic itinerant ferromagnetic system characterized by a density of states that presents a moderately strong peak that is controlled by a specific parameter a and is positioned near the band edge. Specifically, we investigated the superconducting critical temperature, T c , and the zero-temperature superconducting gap, Δ 0 . The analysis is done in a self-consistent way, the BCS mean-field equation being solved together with the electron density equation to trace possible changes in the system’s chemical potential due to the strong correlations between the component electrons. We discussed the density dependence of the superconducting critical temperature and zero-temperature superconducting gap for various values of the control parameter a and of the electron–electron attractive interaction. In the zero temperature limit we derive the system’s phase diagram and discuss the possible fermionic and bosonic regimes of the diagram as function of the strength of the attractive interaction. Content Type Journal Article Pages 1-8 DOI 10.1007/s10948-011-1175-8 Authors A. A. Díaz, Departamento de Física—FACYT, University of Carabobo, Valencia, Venezuela J. J. Rodríguez-Núñez, Lab. SUPERCOMP, Departamento de Física—FACYT, University of Carabobo, Valencia, Venezuela A. A. Schmidt, LANA, Departamento de Matemática, CCNE, UFSM, Santa Maria, Brazil I. Ţifrea, Department of Physics and Astronomy, California State University Fullerton, Fullerton, CA 92834, USA Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    We synthesized as prepared and oxygen annealed Cu 0.5 Tl 0.5 Ba 2 Ca 3− y M y Cu 4 O 12− δ ( y =0 and 1.5 for M=Mg, Be) High Temperature Superconductors (HTSCs) by using the solid state reaction method. It is observed that superconducting properties and the magnitude of the diamagnetism are enhanced by the doping of Mg and Be at the Ca site; this is due to smaller ionic sizes and higher electronegativities of Mg and Be as compared to Ca. Furthermore, interplanar coupling is also improved and shrinking of the axis length is the direct evidence of it. The carrier’s concentration in conducting planes is improved by carrying out post-annealing experiments in the oxygen atmosphere. Moreover, FTIR absorption measurements are also incorporated. Content Type Journal Article Pages 1-7 DOI 10.1007/s10948-011-1156-y Authors Babar Shabbir, Materials Science Laboratory, Department of Physics, Quaid-i-Azam University, 45320 Islamabad, Pakistan Muhammad Imran Malik, BS Department, SEECS, NUST, Sector H-12, Islamabad, Pakistan Nawazish A Khan, Materials Science Laboratory, Department of Physics, Quaid-i-Azam University, 45320 Islamabad, Pakistan Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    The relatively higher electronegative elements (M = Pd, Nb, Bi, Hg) have been partially doped at Tl sites in Cu 0.5 Tl 0.5− x M x Ba 2 O 4− δ ( x =0,0.25) charge reservoir layer of Cu 0.5 Tl 0.5− x M x Ba 2 Ca 2 Cu 3 O 10− δ superconductor. These elements may retain more oxygen in the charge reservoir layer due to their higher electronegativity as compared to Tl, and the higher population of oxygen in the charge reservoir layer can optimize the charge carriers’ density in the conducting CuO 2 planes. The optimum density of mobile charge carriers in the conducting CuO 2 increases Fermi wave-vector K F and Fermi velocity v F of the carriers, which results in the improvement of superconducting properties of the material. Content Type Journal Article Pages 1-5 DOI 10.1007/s10948-011-1157-x Authors M. Mumtaz, Materials Science Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad, 45320 Pakistan Nawazish A. Khan, Materials Science Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad, 45320 Pakistan Faheem Ashraf, Materials Science Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad, 45320 Pakistan Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    We report a simple, reliable method to grow high-quality BaFe 2− x Co x As 2 single-crystal samples without using any fluxing agent. The starting materials for the single-crystal growth come from well-crystallized polycrystalline samples and the highest growing temperature can be 1230°C. The as-grown crystals have typical dimensions of 4×3×0.5 mm 3 with c -axis perpendicular to the shining surface. We find that the samples have very large current carrying ability, indicating that the samples have good potential technological applications. Content Type Journal Article Pages 1-5 DOI 10.1007/s10948-011-1163-z Authors Changjin Zhang, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, 230031 People’s Republic of China Lei Zhang, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, 230031 People’s Republic of China Chuanying Xi, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, 230031 People’s Republic of China Langsheng Ling, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, 230031 People’s Republic of China Wei Tong, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, 230031 People’s Republic of China Shun Tan, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230026 People’s Republic of China Yuheng Zhang, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, 230031 People’s Republic of China Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    Cu 0.5 Tl 0.5 Ba 2 Ca 2− x Pr x Cu 3 O 10− δ superconducting samples, with 0≤ x ≤0.15, were prepared by a single-step solid state reaction on a form of rectangular bar. The prepared samples were characterized using X-ray powder diffraction (XRD) and scanning electron microscope (SEM). The room temperature Vickers microhardness was measured at different loads (0.25–3 N). The experimental results were analyzed using Meyer’s law, Hays–Kendall approach, elastic/plastic deformation model, proportional specimen resistance model, and the indentation-induced cracking (IIC) model. Surprising results were obtained and showed that all samples in the form of rectangular bars exhibited reverse indentation size effect in contrary with those in the form of discs. Vickers microhardness values were decreased as Pr-content increased that consisting with the porosity results. Furthermore, the Young’s modulus was determined using the dynamic resonance technique. A relation between Young’s modulus ( E ) and Vickers microhardness ( H V ) was obtained. Content Type Journal Article Pages 1-10 DOI 10.1007/s10948-011-1150-4 Authors R. Awad, Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt A. I. Abou Aly, Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt M. Kamal, Physics Department, Faculty of Science, Mansoura University, Mansoura, Egypt M. Anas, Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    The main role played by mobile carriers and fluctuation induced conductivity (FIC) in (Cu 0.5 Tl 0.5− x K x )Ba 2 Ca 3 Cu 1 Zn 3 O 12− δ ( x =0, 0.25) superconductor samples are analyzed in the light of the Aslamazov–Larken (AL) theory. The enhancement of three-dimensional (3D) conductivity and grain size is achieved with K-doping at Tl sites in the (Cu 0.5 Tl 0.5− x K x )Ba 2 O 4− δ charge reservoir layer, which are further improved by post-annealing the samples in oxygen. The improvement of these factors causes the increase in cross-over temperature ( T o ), zero resistivity critical temperature { T c ( R =0)} and T c (onset) of diamagnetism to their higher values. We have also evaluated the exponents ( λ 2D and λ 3D ), zero temperature coherence lengths ξ c (0), and interlayer coupling ( J ) for these samples and tried to correlate them to the superconductivity order parameters. Content Type Journal Article Pages 1-7 DOI 10.1007/s10948-011-1148-y Authors M. Mumtaz, Materials Science Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad, 45320 Pakistan Nawazish A. Khan, Materials Science Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad, 45320 Pakistan S. M. Hasnain, Materials Science Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad, 45320 Pakistan Adnan Younis, Materials Science Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad, 45320 Pakistan Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    We report on Gd ion implantation and magnetic characterization of GaN films on sapphire substrates and of bare sapphire and Si substrates to shed light on the mechanism underlying the induced magnetism upon Gd ion implantation. For all three hosts, giant magnetic moments per Gd ion were observed at temperatures of 5 through 300 K. The maximum moment per Gd in GaN was 1800 μ B , while the moments in Gd-implanted Si and sapphire were only slightly smaller. The apparent induced ferromagnetic response was found to be metastable, disappearing after on the order of 50 days at room temperature, except for the implanted sapphire. We argue that our findings support a defect-based picture of magnetism in Gd-implanted semiconductors and insulators. Content Type Journal Article Pages 1-6 DOI 10.1007/s10948-011-1165-x Authors X. Wang, Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, USA C. Timm, Institute of Theoretical Physics, Technische Universtät Dresden, 01062 Dresden, Germany X. M. Wang, Department of Physics, University of Houston, Houston, USA W. K. Chu, Department of Physics, University of Houston, Houston, USA J. Y. Lin, Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, USA H. X. Jiang, Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, USA J. Z. Wu, Department of Physics and Astronomy, University of Kansas, Lawrence, USA Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    In the present study, we report an intercomparison of various physical and electronic properties of MgB 2 and AlB 2 . In particular, the results of phase formation, resistivity ρ ( T ), thermoelectric power S ( T ), magnetization M ( T ), heat capacity ( C P ), and electronic band structure are reported. The original stretched hexagonal lattice with a =3.083 Å, and c =3.524 Å of MgB 2 shrinks in c -direction for AlB 2 with a =3.006 Å, and c =3.254 Å. The resistivity ρ ( T ), thermoelectric power S ( T ) and magnetization M ( T ) measurements exhibited superconductivity at 39 K for MgB 2 . Superconductivity is not observed for AlB 2 . Interestingly, the sign of S ( T ) is +ve for MgB 2 the same is −ve for AlB 2 . This is consistent with our band structure plots. We fitted the experimental specific heat of MgB 2 to Debye–Einstein model and estimated the value of Debye temperature ( Θ D ) and Sommerfeld constant ( γ ) for electronic specific heat. Further, from γ , the electronic density of states ( DOS ) at Fermi level N ( E F ) is calculated. From the ratio of experimental N ( E F ) and the one being calculated from DFT , we obtained value of λ to be 1.84, thus placing MgB 2 in the strong coupling BCS category. The electronic specific heat of MgB 2 is also fitted below T c using α -model and found that it is a two gap superconductor. The calculated values of two gaps are in good agreement with earlier reports. Our results clearly demonstrate that the superconductivity of MgB 2 is due to very large phonon contribution from its stretched lattice. The same two effects are obviously missing in AlB 2 , and hence it is not superconducting. DFT calculations demonstrated that for MgB 2 , the majority of states come from σ and π 2p states of boron on the other hand σ band at Fermi level for AlB 2 is absent. This leads to a weak electron phonon coupling and also to hole deficiency as π bands are known to be of electron type, and hence obviously the AlB 2 is not superconducting. The DFT calculations are consistent with the measured physical properties of the studied borides, i.e., MgB 2 and AlB 2 . Content Type Journal Article Pages 1-7 DOI 10.1007/s10948-011-1146-0 Authors Devina Sharma, Quantum Phenomena and Applications Division, National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi, 110012 India Jagdish Kumar, Quantum Phenomena and Applications Division, National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi, 110012 India Arpita Vajpayee, Quantum Phenomena and Applications Division, National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi, 110012 India Ranjan Kumar, Department of Physics, Punjab University, Chandigrah, 160014 India P. K. Ahluwalia, Department of Physics, Himachal Pradesh University, Summerhill, Shimla, 171005 India V. P. S. Awana, Quantum Phenomena and Applications Division, National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi, 110012 India Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    In this work, we report a systematic study on the microstructure and magnetic properties of isotropic M-type SrNd x Fe 12− x O 19 hexaferrites ( x =0.0, 0.1, 0.2, 0.3, 0.4, 0.5) obtained by conventional ceramic process. According to DRX analysis, a solid solution is formed for Nd contents up to x =0.1, while a composite Sr(NdFe) 12 O 19 /SrFeO 3 microstructure results for x 〉0.1. Interesting combinations of hard magnetic properties were obtained for the whole compositional series including increasing coercivity values (up to 329 kA/m for x =0.5) with increasing Nd concentration, together with high Curie temperatures (around 731 K). Results are interpreted in terms of the Nd incorporation into the unit cell as well as within the frame of the nucleation controlled mechanism as the coercivity source for this kind of materials. Content Type Journal Article Pages 1-5 DOI 10.1007/s10948-011-1193-6 Authors T. J. Pérez-Juache, Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Av. Salvador Nava Martínez S/N Zona Universitaria, San Luis Potosí, SLP CP 78294, Mexico I. Betancourt, Departamento de Materiales Metálicos y Cerámicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México D.F., 04510 México S. A. Palomares-Sánchez, Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Av. Salvador Nava Martínez S/N Zona Universitaria, San Luis Potosí, SLP CP 78294, Mexico M. Mirabal García, Instituto de Física, Universidad Autónoma de San Luis Potosí, Av. Dr. Nava S/N, Zona Universitaria, 78290 San Luis Potosí, SLP, México J. A. Matutes-Aquino, Centro de Investigación en Materiales Avanzados, Chihuahua, Chih., México A. L. Guerrero-Serrano, Centro de Investigación en Materiales Avanzados, Chihuahua, Chih., México Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    The effect of nitrogen addition on the morphology, magnetic anisotropy, and magnetoresistance properties of Co–Ni–N granular thin films were investigated. The films were grown by electrodeposition onto aluminum substrates at room temperature. By a complex process of cationic catalysis occurring at the cathode/electrolyte interface, nitrogen is adsorbed in the Co–Ni film. Finally, a granular film grows by a tridimensional progressive nucleation mechanism. The nature of the grains and of the interface between them influences exchange interactions between grains, which play an important role in determining the magnetic anisotropy. From the magnetic measurements, we found that the magnetic anisotropy constant varied in the range K eff =(−21.5÷36.6)×10 4  J⋅m −3 and the coercivity varied between H c =(13÷67) kA⋅m −1 depending on the sodium nitrate content in the plating bath. The Co–Ni–N granular thin films display large values (∼160%) of magnetoresistance. These large values of magnetoresistance make such structures attractive for applications as sensitive magnetic field sensors. Content Type Journal Article Pages 1-7 DOI 10.1007/s10948-011-1188-3 Authors S. I. Tanase, Faculty of Physics, “Alexandru Ioan Cuza” University, Iasi, 700506 Romania D. Pinzaru (Tanase), Faculty of Physics, “Alexandru Ioan Cuza” University, Iasi, 700506 Romania V. Georgescu, Faculty of Physics, “Alexandru Ioan Cuza” University, Iasi, 700506 Romania Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    Na-doped single domain YBa 2− x Na x Cu 3 O 7− δ (YBCO, x =0.05, 0.1, 0.15, 0.2, 0.25, 0.3) bulk superconductors were prepared by a modified melt textured process and the effect of Na substitution on the levitation force of YBCO bulks have been investigated. The maximum levitation forces (MLF) are much different for samples with a different Na element content. It is found that the optimum Na element content in YBCO for the strong MLF is around x =0.2. It is also found that the addition of Na could reduce and increase the ATH of the YBCO platelet while x less than 0.1 and larger than 0.1, some of adjacent platelet grains are well intergrown each other in the sample with x =0.2 comparing to the other samples and the influence of the Na addition on the Y211 particle size is not obvious. Content Type Journal Article Pages 1-4 DOI 10.1007/s10948-011-1183-8 Authors W. M. Yang, Department of Physics, Shaanxi Normal University, Xi’an, Shaanxi 710062, China Y. L. Tang, Department of Physics, Shaanxi Normal University, Xi’an, Shaanxi 710062, China G. Z. Li, Department of Physics, Shaanxi Normal University, Xi’an, Shaanxi 710062, China X. X. Chao, Department of Physics, Shaanxi Normal University, Xi’an, Shaanxi 710062, China J. Ma, Department of Physics, Shaanxi Normal University, Xi’an, Shaanxi 710062, China Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    An analysis of the properties of a family based on lead-barium substitution in the M-type hexaferrite is presented. The samples were prepared by the ceramic method according to the general formula Pb x Ba 1− x Fe 12 O 19 . The barium content was varied with x =0.1, 0.3, 0.5, 0.7, and 0.9; no secondary phases were detected in any composition. Rietveld refinement analysis was done in order to determinate crystallographic parameters, content of phases and degree of substitution. The effects of the barium on the morphological and magnetic properties were studied. Iron Mössbauer spectroscopy was used for determining the hyperfine parameters of the iron nucleus and their environment; also, the cationic occupancy was evaluated and the results were checked with X-ray refinement results. Content Type Journal Article Pages 1-6 DOI 10.1007/s10948-011-1181-x Authors A. L. Guerrero-Serrano, Centro de Investigación en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, 31120 Chihuahua, México T. J. Pérez-Juache, Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, Centro, 78000 San Luis Potosí, SLP, México M. Mirabal-García, Instituto de Física, Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, Centro, 78000 San Luis Potosí, SLP, México J. A. Matutes-Aquino, Centro de Investigación en Materiales Avanzados, S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, 31120 Chihuahua, México S. A. Palomares-Sánchez, Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, Centro, 78000 San Luis Potosí, SLP, México Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    The theoretical study of the superconducting state parameters (SSP) namely electron–phonon coupling strength λ , Coulomb pseudopotential μ ∗ , transition temperature T C , isotope effect exponent α , and effective interaction strength N O V of 4d-transition metals superconductors have been made extensively in the present work using a model potential formalism for the first time. In the present computation, the use of pseudo-alloy-atom model (PAA) is proposed and found successful. A considerable influence of various exchange and correlation functions on λ and μ ∗ is found from the present study. The present results of the SSP are found in qualitative agreement with the available experimental data wherever exist. Content Type Journal Article Pages 1-8 DOI 10.1007/s10948-011-1182-9 Authors Aditya M. Vora, Parmeshwari 165, Vijaynagar Area, Hospital Road, Bhuj–Kutch, 370 001 Gujarat, India Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    In this study, the effects of partial Sb 3+ ion substitutions for the Y sites and the Cu sites on the superconducting properties of YBa 2 Cu 3 O y (Y123) ceramic superconductors were investigated. The samples were prepared by the conventional solid-state reaction method and the properties of the samples were investigated by means of X-ray diffraction, AC magnetic susceptibility measurements, scanning electron microscope, and energy dispersive X-ray analysis. The critical temperatures were determined to be in the range of 80–92 K for both Systems I and II. It was found that Sb-addition leads to the formation of the non-superconducting YBa 2 SbO 6 phase, which has a negative effect on the critical temperature, since the highest critical temperature was measured for pure Y123. However, the increasing substitution level has a negligible effect on the X-ray diffraction analysis peak intensities of the superconducting phases. In addition, SEM images showed that Sb substitution decreases the grain size and modifies the microstructure development, which makes the samples denser. Content Type Journal Article Pages 1-13 DOI 10.1007/s10948-011-1180-y Authors Gönül B. Akyüz, Physics Department, Adnan Menderes University, 09100 Aytepe, Aydın, Turkey Kemal Kocabaş, Faculty of Science, Physics Department, Dokuz Eylül University, 35160 Buca, İzmir, Turkey Aylin Yıldız, Faculty of Science, Physics Department, Dokuz Eylül University, 35160 Buca, İzmir, Turkey Lütfi Özyüzer, Department of Physics, İzmir Institute of Technology, 35430 Urla, İzmir, Turkey Muhsin Çiftçioğlu, Chemical Engineering Department, İzmir Institute of Technology, 35430 Urla, İzmir, Turkey Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    As experimentally well established, undoped LaFeAsO is antiferromagnetic below 137 K with the magnetic moments lying on the Fe sites. We determine the orthorhombic body-centered group Imma (74) as the space group of the experimentally observed magnetic structure in the undistorted lattice, i.e., in a lattice possessing no structural distortions in addition to the magnetostriction. We show that LaFeAsO possesses a partly filled “magnetic band” with Bloch functions that can be unitarily transformed into optimally localized Wannier functions adapted to the space group Imma . This finding is interpreted in the framework of a nonadiabatic extension of the Heisenberg model of magnetism, the nonadiabatic Heisenberg model. Within this model, however, the magnetic structure with the space group Imma is not stable but can be stabilized by a (slight) distortion of the crystal turning the space group Imma into the space group Pnn 2 (34). This group-theoretical result is in accordance with the experimentally observed displacements of the Fe and O atoms in LaFeAsO as reported by Clarina de la Cruz et al. (Nature 453:899, 2008 ). Content Type Journal Article Pages 1-15 DOI 10.1007/s10948-011-1177-6 Authors Ekkehard Krüger, Institut für Materialwissenschaft, Materialphysik, Universität Stuttgart, 70569 Stuttgart, Germany Horst P. Strunk, Institut für Materialwissenschaft, Materialphysik, Universität Stuttgart, 70569 Stuttgart, Germany Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    The first principles FLAPW–GGA method was used for the comparative study of the structural and electronic properties of three related tetragonal ThCr 2 Si 2 -type phases KFe 2 Ch 2 , where Ch are S, Se, and Te. The main trends in electronic bands, densities of states, and Fermi surfaces for A Fe 2 Ch 2 were analyzed in relation to their structural parameters. We found that anion replacements (S↔Se↔Te) produce no critical changes in the electronic structure of KFe 2 Ch 2 phases. On the other hand, our analysis of structural and electronic parameters for hypothetical KFe 2 Te 2 allows us to propose this system as a perspective parent phase for search of new iron-chalcogenide superconducting materials. Content Type Journal Article Pages 1-7 DOI 10.1007/s10948-011-1184-7 Authors I. R. Shein, Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 620990 Ekaterinburg, Russia A. L. Ivanovskii, Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 620990 Ekaterinburg, Russia Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description: Erratum to: Cooperative Time-Reversal Symmetry Breaking Induced by a Magnetic Field in a Quasi-2D d-Wave Superconductor Content Type Journal Article Pages 1-1 DOI 10.1007/s10948-011-1191-8 Authors S. Char fi-Kaddour, Laboratoire de Physique de la Matière Condensée, Département de Physique, Faculté des Sciences de Tunis, 1060 Tunis, Tunisia A. Ben Ali, Laboratoire de Physique de la Matière Condensée, Département de Physique, Faculté des Sciences de Tunis, 1060 Tunis, Tunisia M. Héritier, Laboratoire de Physique des Solides, associé au CNRS, Bâtiment 510, Université Paris-Sud, 91405 Orsay, France R. Bennaceur, Laboratoire de Physique de la Matière Condensée, Département de Physique, Faculté des Sciences de Tunis, 1060 Tunis, Tunisia Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    Bulk superconducting samples of type GdBa 2 Cu 3− x Ru x O 7− δ , Gd-123, with x =0.0–0.3 were prepared by the conventional solid-state reaction technique. X-ray powder diffraction (XRD), scanning electron microscope (SEM), electron dispersive X-ray (EDX) and electrical-resistivity measurements were performed in order to investigate the effect of Ru 4+ ions substitution on Gd-123 phase. Enhancement of both phase formation and the superconducting transition temperature T c for GdBa 2 Cu 3− x Ru x O 7− δ phase up to x =0.05 was observed from XRD and electrical-resistivity measurement, respectively. This enhancement was confirmed with the calculated relative volume fraction. For x 〉0.05, suppression of both phase formation and T c was obtained and the superconductivity was completely destroyed around x =0.3. The normal-state electrical resistivity was analyzed by the two- and three-dimensional variable range hopping (2D-VRH and 3D-VRH) and Coulomb gap CG. The results showed that the dominant mechanism was CG for x ≤0.075, while was 3D-VRH for x ≥0.15. Content Type Journal Article Pages 1-10 DOI 10.1007/s10948-011-1187-4 Authors R. Awad, Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt A. I. Abou-Aly, Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt S. A. Mahmoud, Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt M. ME. Barakat, Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    This paper presents the synthesis and characterization of the new superconducting compounds with nominal composition, RE 3 Ba 5 Cu 8 O 18 , RE=Y, Sm and Nd. The onset critical temperatures of the present samples are 97.5, 97 and 95 K for the RE=Y, Sm and Nd, respectively. The first two values are the highest for the RE–Ba–Cu–O superconductors recorded to date. The RE 3 Ba 5 Cu 8 O 18 samples crystallize in the orthorhombic system, with increased unit cell volume as Sm and Nd replace the element Y. Content Type Journal Article Pages 1-4 DOI 10.1007/s10948-011-1176-7 Authors Ugur Topal, TUBITAK-UME (National Metrology Institute), 41470 Gebze-Kocaeli, Turkey Mustafa Akdogan, Department of Physics, Abant Izzet Baysal University, 14280 Bolu, Turkey Husnu Ozkan, Department of Physics, Middle East Technical University, 06531 Ankara, Turkey Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    Epitaxial growth of CeO 2 buffer layers on biaxially textured (001)Ni tapes was studied using pulsed laser deposition. Relationships between microstructure and deposition parameters were systematically studied in order to develop reliable long tape coating processes. It was found that orientation and texture of CeO 2 buffer layers were sensitive to deposition parameters. X-ray diffraction analyses showed that CeO 2 buffer layers had pure (001) orientation at 860 °C. Under optimized deposition conditions, highly (001) oriented CeO 2 buffer layers have been achieved at a high deposition rate of 1.5 nm/s in-plane texture and out-plane texture of CeO 2 buffer layers were 4.25 degrees and 5.85 degrees, respectively. Content Type Journal Article Pages 1-5 DOI 10.1007/s10948-011-1172-y Authors Ying Wang, Key Laboratory of Artificial Structure and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800# Dong Chuan Road, Shanghai, 200240 P.R. China Linfei Liu, Key Laboratory of Artificial Structure and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800# Dong Chuan Road, Shanghai, 200240 P.R. China Huaran Liu, Key Laboratory of Artificial Structure and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800# Dong Chuan Road, Shanghai, 200240 P.R. China Xiaokun Song, Key Laboratory of Artificial Structure and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800# Dong Chuan Road, Shanghai, 200240 P.R. China Dan Hong, Key Laboratory of Artificial Structure and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800# Dong Chuan Road, Shanghai, 200240 P.R. China Da Xu, Key Laboratory of Artificial Structure and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800# Dong Chuan Road, Shanghai, 200240 P.R. China Shengping Zhu, Key Laboratory of Artificial Structure and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800# Dong Chuan Road, Shanghai, 200240 P.R. China Yijie Li, Key Laboratory of Artificial Structure and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800# Dong Chuan Road, Shanghai, 200240 P.R. China Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description: Reflection on the 2nd International Conference on Superconductivity and Magnetism-ICSM2010 Content Type Journal Article Pages 1-4 DOI 10.1007/s10948-011-1185-6 Authors Ali Gencer, Faculty of Sciences, Physics Department, Ankara University, Tandoğan, 06100 Ankara, Turkey Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    This study reports the effect of Gd addition on magnetic and structural properties of Bi 1.8 Pb 0.35 Sr 1.9 Ca 2.1 Cu 3 Gd x O y superconductor with x =0, 0.1, 0.2, 0.3, 0.4 and 0.5 by means of ac susceptibility measurements at various ac fields (ranging from 270 to 1352 A/m) and scanning electron microscopy (SEM) images. Critical onset ( and loss peak temperatures ( T p ) were qualitatively estimated from the ac susceptibility curves. The peak temperature at zero ac-magnetic field ( T p0 ) and intergrain critical current densities ( J c ) were theoretically calculated from the ac susceptibility plots via the critical state models. The results show that peak temperatures and critical current densities were found to decrease with increasing Gd addition. Moreover, using a self-field approximation together with J c dependence on temperature, the characteristic length ( L c ) associated with the pinning force is estimated to be approximately the same as the average grain size ( R g ) of the pinning center because of the linear decrease in J c with increasing temperature. Surface morphology and grain connectivity of the samples were also obtained to degrade with increase in the Gd addition from SEM investigations. Content Type Journal Article Pages 1-7 DOI 10.1007/s10948-011-1174-9 Authors G. Yildirim, Department of Physics, Abant Izzet Baysal University, Bolu, 14280 Turkey Y. Zalaoglu, Department of Physics, Osmaniye Korkut Ata University, Osmaniye, 80000 Turkey M. Akdogan, Department of Physics, Abant Izzet Baysal University, Bolu, 14280 Turkey S. P. Altintas, Department of Physics, Abant Izzet Baysal University, Bolu, 14280 Turkey A. Varilci, Department of Physics, Abant Izzet Baysal University, Bolu, 14280 Turkey C. Terzioglu, Department of Physics, Abant Izzet Baysal University, Bolu, 14280 Turkey Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    In this paper, we report experimental results concerning the magnetic properties and the magnetoresistance effect of [Fe/Pt] n and [Pt/Fe] n electrodeposited multilayers. Two series of multilayers starting with Pt and Fe layers, respectively, were grown onto glass substrate covered with electroless deposited amorphous Ni. We investigated the effect of the seed layer (Pt or Fe) and Pt layer thicknesses on the magnetic and magnetoresistance properties of electrodeposited multilayers. The structure and morphology of the samples were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). The hysteresis loops of the [Fe/Pt] n and [Pt/Fe] n multilayers showed that the magnetic properties strongly depend on the Pt thickness and on the seed layer (the first layer deposited onto the glass substrate). [Fe/Pt] n and [Pt/Fe] n electrodeposited multilayers display magnetoresistance (∼15%) effect which can be explained mainly by the spin-dependent scattering of conduction electrons between Fe layers through a Pt layer and by the existence of anti-ferromagnetic coupling between subsequent Fe layers. The existence of a GMR effect in Fe/Pt multilayers is very promising for technological applications (e.g., magnetoresistance sensors). Content Type Journal Article Pages 1-8 DOI 10.1007/s10948-011-1173-x Authors D. Pinzaru (Tanase), Faculty of Physics, “Al. I. Cuza” University, Bv. Carol I, No. 11, 700506 Iasi, Romania S. I. Tanase, Faculty of Physics, “Al. I. Cuza” University, Bv. Carol I, No. 11, 700506 Iasi, Romania P. Pascariu, Faculty of Physics, “Al. I. Cuza” University, Bv. Carol I, No. 11, 700506 Iasi, Romania L. Vlad, Faculty of Physics, “Al. I. Cuza” University, Bv. Carol I, No. 11, 700506 Iasi, Romania C. Pirghie, Department of Mechanical Engineering, ”Stefan cel Mare” University, 720225 Suceava, Romania V. Georgescu, Faculty of Physics, “Al. I. Cuza” University, Bv. Carol I, No. 11, 700506 Iasi, Romania Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    (Tl 1− x Bi x )(Sr 2− y Ba y )Ca 3 Cu 4 O z ((Tl,Bi)-1234) samples ( x =0.1–0.3, y =0.4–1.5) were synthesized under ambient pressure by using a two-step solid-state reaction method to investigate the effect of Ba substitution on the formation and superconducting properties of the (Tl,Bi)-1234 phase. X-ray diffraction analysis shows that nearly single-phased samples are obtained for (Tl 0.8 Bi 0.2 )(Sr 2− y Ba y )Ca 3 Cu 4 O z (0.8≤ y ≤1.2), suggesting that control of the composition ratio of Sr and Ba in the bridging layer is a key to stabilizing the 1234-type structure. The critical temperature for the nearly single-phased samples remained between 106.9 K and 109.1 K and was not significantly affected by the change in the Ba content. Content Type Journal Article Pages 1-5 DOI 10.1007/s10948-011-1179-4 Authors H. K. Lee, Department of Physics, Kangwon National University, Chuncheon, 200-701 Republic of Korea Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    In this paper we examine the role of crystal chemistry factors in creating conditions for formation of magnetoelectric ordering in BiFeO 3 . It is generally accepted that the main reason of the ferroelectric distortion in BiFeO 3 is concerned with a stereochemical activity of the Bi lone pair. However, the lone pair is stereochemically active in the paraelectric orthorhombic ß-phase as well. We demonstrate that a crucial role in emerging of phase transitions of the metal-insulator, paraelectric-ferroelectric and magnetic disorder-order types belongs to the change of the degree of the lone pair stereochemical activity—its consecutive increase with the temperature decrease. Using the structural data, we calculated the sign and strength of magnetic couplings in BiFeO 3 in the range from 945 °C down to 25 °C and found the couplings, which undergo the antiferromagnetic → ferromagnetic transition with the temperature decrease and give rise to the antiferromagnetic ordering and its delay in regard to temperature, as compared to the ferroelectric ordering. We discuss the reasons of emerging of the spatially modulated spin structure and its suppression by doping with La 3+ . Content Type Journal Article Pages 1-17 DOI 10.1007/s10948-011-1178-5 Authors L. M. Volkova, Institute of Chemistry, Far Eastern Branch of Russian Academy of Science, 159, 100-Let Prosp., Vladivostok, 690022 Russia D. V. Marinin, Institute of Chemistry, Far Eastern Branch of Russian Academy of Science, 159, 100-Let Prosp., Vladivostok, 690022 Russia Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    In this work, we present a systematic study on the effect of sintering time on the superconducting behavior of the Hg 0.6 Pb 0.25 Sb 0.15 Ba 2 Ca 2 Cu 3 O 8+ δ compound. Bulk polycrystalline samples have been prepared by a solid state reaction method. It has been observed that the as grown Hg 0.6 Pb 0.25 Sb 0.15 Ba 2 Ca 2 Cu 3 O 8+ δ compound corresponds to the 1223 phase. Electrical resistivity, using the four probe technique, was used to find the transition temperature T c . The highest T c (off) and T c (on) were found to be 116 K and 132 K, respectively, for the sample preparation with a sintering time of 24 hours. X-ray diffraction (XRD) analysis showed a tetragonal structure with a decrease of the c -axis lattice constant with an increase of the sintering time. It was found that the increase of the sintering time produces a change in the c / a and volume fraction V Ph(1223) . Content Type Journal Article Pages 1-4 DOI 10.1007/s10948-011-1153-1 Authors Kareem A. Jasim, Department of Physics, College of Education, Ibn-Al-Haithem, University of Baghdad, Baghdad, Iraq Tariq J. Alwan, Department of Physics, College of Education, Al-Mustansiriyah University, Baghdad, Iraq H. K. Al-Lamy, Department of Physics, College of Science, University of Baghdad, Baghdad, Iraq H. L. Mansour, Department of Physics, College of Education, Al-Mustansiriyah University, Baghdad, Iraq Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    La 0.85 Ag 0.15 MnO 3 , the colossal magnetoresistance compound was prepared and the neutron powder diffraction patterns at different temperatures down to 19 K were recorded to study their crystal structure and magnetic properties. These patterns were analyzed by the Rietveld refinement technique and are found to be free from any impurity phase. The compound is found to crystallize in a mixture of and Pnma space group and the phase fraction is found to vary with temperature. A cross-over from dominated high temperature phase to Pnma dominated low temperature phase at around 130 K was observed. At low temperatures, especially below 285 K, the diffraction patterns could be refined by including the magnetic reflections corresponding to ferromagnetic structure. The refined magnetic moment of Mn ions is found to be along b axis of the unit cell with a maximum moment of 3.74 μ B at 19 K and this value is comparable to the saturation magnetization observed at 20 K from magnetization measurement. Content Type Journal Article Pages 1-5 DOI 10.1007/s10948-011-1147-z Authors B. Samantaray, Department of Physics, Indian Institute of Technology Guwahati, Guwahati, 781039 India S. K. Srivastava, Department of Physics, Indian Institute of Technology Guwahati, Guwahati, 781039 India S. Ravi, Department of Physics, Indian Institute of Technology Guwahati, Guwahati, 781039 India I. Dhiman, Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 India A. Das, Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 India Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    A theoretical calculation on YbOs 4 Sb 12 filled skutterudite is reported. The calculated energy bands yield indication of a semimetallic behavior, while the projected density of states provide support for the existence of hybridization formed by Yb f-, Os d-, and Sb p-states. From the analysis of the energy bands that crosses the E f , it is possible to infer a high effective mass; this value is added to the existence of a strong hybridization yielded indication of the heavy Fermion behavior for this compound which agrees with the experimental information available. The absence of a minigap provides an indication that this compound is not likely to serve as a good thermoelectric material, unless doped in a certain direction as to enhance the probability to open the necessary minigap between the valence and conduction bands. Crystal orbital overlap population analysis yielded indication for the absence of a ferromagnetic instability. Content Type Journal Article Pages 1-6 DOI 10.1007/s10948-011-1152-2 Authors Donald H. Galvan, Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autónoma de México, Apartado Postal 2681, CP 22800 Ensenada, B.C., México Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    Co 3 O 4 /CoO nanoparticles have been synthesized by a simple method which is based on the ball-milling and calcination of cobalt acetate and citric acid. The samples were characterized using X-ray diffraction, transmission electron microscope, and Fourier transform infrared spectroscopy. The results show that Co 3 O 4 nanoparticles with an average particle size of ∼40 nm can be obtained by calcination of ball-milled precursors at relatively low temperature (350 °C) for 3 hours. It should be noted that it is possible to control the size of Co 3 O 4 particles by calcination temperature, calcination time and also by ball-milling duration using this method. Meanwhile, the pure CoO nanoparticles were obtained successfully by thermal decomposition of Co 3 O 4 at 950 °C and quickly quenching to liquid nitrogen. Content Type Journal Article Pages 1-4 DOI 10.1007/s10948-011-1141-5 Authors I. Manouchehri, Department of Physics, Isfahan University of Technology, Isfahan, 84156-83111 Iran P. Kameli, Department of Physics, Isfahan University of Technology, Isfahan, 84156-83111 Iran H. Salamati, Department of Physics, Isfahan University of Technology, Isfahan, 84156-83111 Iran Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    We investigate the spin-valley current in a strain-engineered graphene magnetic system, normal region (N)/strain region(S)/ferromagnetic region (F)/normal region (N) junction. Locally strained region S leads to valley-dependent current, and ferromagnetic region F leads to the spin-dependent current. We find that pure valley current can be created easily by applying the real-vector potential that is equal to the pseudo-vector potential caused by strains in the S-region. In this work, we focus on the spin current in each valley when exchange field is applied in the F-region, and find that the linear control of spin-valley polarization by gate potential is possible. It is also found that when the current is carried only by the carriers in one valley (pure valley current), pure spin-up current can be linearly altered to pure spin-down current by tuning the gate potential, in the case of very large-F-thickness junction. Our work is applicable for devising controllable spin-valley-current electronics circuits. Content Type Journal Article Pages 1-8 DOI 10.1007/s10948-011-1138-0 Authors Bumned Soodchomshom, Thailand Center of Excellence in Physics, Commission Higher on Education, Ministry of Education, Bangkok, 10400 Thailand Peerasak Chantngarm, Department of Electronics and Telecommunication Engineering, Faculty of Engineering, Pathumwan Institute of Technology, Bangkok, 10330 Thailand Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    Here, the superconducting and AC/DC magnetic properties of REBa 2 Cu 3 O 7− δ (RE: Eu, Gd, Ho and Er) are investigated in order to understand the inter-granular and intra-granular behavior of these compounds. These compounds were prepared by standard solid-state reaction route. ErBa 2 Cu 3 O 7− δ (Er-123) and HoBa 2 Cu 3 O 7− δ (Ho-123) (consisting of heavier rare earth) show higher orthorhombic splitting in their XRD patterns than those observed for EuBa 2 Cu 3 O 7− δ (Eu-123) and GdBa 2 Cu 3 O 7− δ (Gd-123) (consisting of lighter rare earth). Even though Eu, Gd, Ho and Er are magnetic elements, substitution of these at Y site in Y-123 does not change the superconducting transition temperature ( T c ). Er-123 and Ho-123 exhibit very sharp superconducting transition while Eu-123 and Gd-123 exhibit relatively broad transition with little hump at the lower part of transition close to the long-range superconducting state with zero resistance. In addition to that, Eu-123 and Gd-123 show relatively higher normal state resistivity than those of Er-123 and Ho-123. The AC susceptibility measurements reveal that these compounds possess different strength of inter-granular couplings. The hump in the superconducting transition of Eu and Gd is not due to the lack of inter-grain couplings in these samples because of having better grain connectivity in the samples as compared to other rare earth elements in REBa 2 Cu 3 O 7− δ system. Though intra-grain peak is insensitive to the applied magnetic field, inter-grain peak is sensitive to the applied magnetic field. Content Type Journal Article Pages 1-7 DOI 10.1007/s10948-011-1139-z Authors N. P. Liyanawaduge, Industrial Technology Institute, P.O. Box 363, Baudhaloka Mawatha, Colombo 07, Sri Lanka Anuj Kumar, National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi, 110012 India B. S. B. Karunarathne, University of Peradeniya, Peradeniya, 20400 Sri Lanka Amita Malik, Dyal Singh College, Lodhi Road, New Delhi, 110003 India H. Kishan, National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi, 110012 India V. P. S. Awana, National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi, 110012 India Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    In this work, we report experimental results concerning the giant magnetoresistance effect and the magnetic properties of [Co/Zn] n and [Zn/Co] n electrodeposited multilayers. Two series of multilayers starting with Co and Zn layers, respectively, were grown onto Cu (100) substrate under identical conditions. We investigated the effect of the seed layer (Co or Zn) and Zn layer’s thicknesses on the magnetic and magnetoresistant properties of electrodeposited multilayers. We found out that the magnetic anisotropy and the shape of the hysteresis cycle are strongly influenced by the multilayer features. The magnetic properties of the [Co/Zn] n and [Zn/Co] n strongly depend on the Zn thickness and on the seed layer (the first layer deposited onto the Cu substrate). The coercivity fields varied between (145 Oe–208 Oe) as a function of the Zn layer’s thicknesses. [Co/Zn] n and [Zn/Co] n electrodeposited multilayers display magnetoresistance (14%) effect which can be explained mainly by the exchange interaction among neighboring layers and by the spatially inhomogeneous magnetic structure of the nanostructured multilayer; in addition, the thickness of the Zn interlayer has an important role on the transportation and diffusion processes. Content Type Journal Article Pages 1-7 DOI 10.1007/s10948-011-1145-1 Authors P. Pascariu, Faculty of Physics, “Alexandru Ioan Cuza” University, Iaşi, 700506 Romania S. I. Tanase, Faculty of Physics, “Alexandru Ioan Cuza” University, Iaşi, 700506 Romania D. Pinzaru (Tanase), Faculty of Physics, “Alexandru Ioan Cuza” University, Iaşi, 700506 Romania V. Georgescu, Faculty of Physics, “Alexandru Ioan Cuza” University, Iaşi, 700506 Romania Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    The compounds Gd 1− x Nd x BaSrCu 3 O 7− δ (where x =0, 0.1 and 0.2) and Gd 1− x Dy x BaSrCu 3 O y (where x =0, 0.1 and 0.3) were synthesized using the solid state reaction technique. The tetragonal crystallization of the compounds was identified by powder X-ray diffraction. The microrange crystallite formation and the substitution elements present in the compounds were observed by SEM and EDX analyses. The suppression of superconducting transition temperature and the variation of magnetization parameters for the substitution of rare-earth magnetic elements Nd and Dy ions were observed by low-temperature electrical resistance and magnetization measurements. Content Type Journal Article Pages 1-8 DOI 10.1007/s10948-011-1137-1 Authors A. Manigandan, Department of Physics, Anna University Chennai, Chennai, 600025 India V. Anbarasu, Department of Physics, Anna University Chennai, Chennai, 600025 India K. Sivakumar, Department of Physics, Anna University Chennai, Chennai, 600025 India Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    We fabricated CeO 2 films using pulsed laser deposition (PLD) for YBa 2 Cu 3 O 7− δ coated conductors on Ni–5 at.%W alloy substrates and investigated the effect of Ni–5 at.%W tapes on the epitaxial growth and surface morphologies of CeO 2 deposited on various substrates at various temperatures ranging from 650 to 770 °C. The texture and microstructure of substrates and CeO 2 films were measured by X-ray diffraction (XRD), optical microscope (OM), field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM). It was found that the texture and microstructure of Ni–5 at.%W substrates, such as Ni(111), grain size, the depth of grain boundary grooves and surface roughness, affected the growth of CeO 2 films. Especially, the depth of grain boundary grooves of substrates resulted in high intensity of CeO 2 (111) peak and high surface roughness of CeO 2 films. We also found that high growth temperature effectively reduced the influence of substrate surface roughness on the epitaxial growth of CeO 2 films. CeO 2 films with high in-plane and out-of-plane alignments (Δ φ =5.54°, Δ ω =3.40°) were obtained under optimum condition. Content Type Journal Article Pages 1-7 DOI 10.1007/s10948-011-1136-2 Authors Shengping Zhu, Key Laboratory of Artificial Structures and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240 P.R. China Linfei Liu, Key Laboratory of Artificial Structures and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240 P.R. China Da Xu, Key Laboratory of Artificial Structures and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240 P.R. China Huaran Liu, Key Laboratory of Artificial Structures and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240 P.R. China Xiaokun Song, Key Laboratory of Artificial Structures and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240 P.R. China Dan Hong, Key Laboratory of Artificial Structures and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240 P.R. China Wang Ying, Key Laboratory of Artificial Structures and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240 P.R. China Yijie Li, Key Laboratory of Artificial Structures and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240 P.R. China Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    SmFeAsO 0.8 F 0.2 wires with composite Cu/Nb or Ta sheaths have been fabricated using an in situ powder-in-tube method. Cu diffusion into the core was observed, which led to a fuzzy boundary between the sheath and core for Cu/Nb-sheathed SmFeAsO 0.8 F 0.2 wires, and destroyed the superconducting phase of SmFeAsO 0.8 F 0.2 . However, superconductivity has been observed in the Ta-sheathed SmFeAsO 0.8 F 0.2 wires with T c =52.5 K. A severe weak-link effect depressed the development of global supercurrent. A peak effect with a strongly temperature-dependent peak field H peak has been observed in the J c – H curves over the range 10–40 K. The H – T phase diagram was similar to that of a previous report. Content Type Journal Article Pages 1-5 DOI 10.1007/s10948-011-1197-2 Authors Y. L. Chen, Key Laboratory of Advanced Technology of Materials (Ministry of Education of China), Superconductivity R&D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031, China Y. J. Cui, Key Laboratory of Advanced Technology of Materials (Ministry of Education of China), Superconductivity R&D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031, China H. Zhang, Key Laboratory of Advanced Technology of Materials (Ministry of Education of China), Superconductivity R&D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031, China C. H. Cheng, School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW Australia Y. Zhao, Key Laboratory of Advanced Technology of Materials (Ministry of Education of China), Superconductivity R&D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031, China Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    In order to clarify the mechanisms in charge of broadening of resistive transition R ( T ) in magnetic fields of bismuth-based polycrystalline high- T C superconductor (HTSC), a comparative study of Bi 1.8 Pb 0.3 Sr 1.9 Ca 2 Cu 3 O x (BSCCO) and YBa 2 Cu 3 O 7− δ (YBCO) have been performed. Magnetoresistive effects and irreversibility line obtained from magnetic measurements have been studied. It was established that (1) for YBCO, the smooth part of R ( T ) dependence unambiguously corresponds to dissipation in the intergrain boundaries for arbitrary magnetic fields; (2) for polycrystalline BSCCO, the smooth part of R ( T ) dependences correspond to dissipation within intergrain boundary subsystem in the field range H 〈10 2 Oe only, while standard measurements of R ( T ) dependences in magnetic field range H 〉10 2 Oe reflect the dissipation processes occurring both in intergrain boundary and HTSC grain subsystems; (3) for the high-field range, the contribution from intergrain boundaries of BSCCO can be distinguished from magnetoresistance R ( H ) dependences obtained at high enough current density on textured samples. It is proposed that various magneto-resistive properties of these classical HTSC systems are due comparatively weak pinning in BSCCO. Content Type Journal Article Pages 1-8 DOI 10.1007/s10948-011-1166-9 Authors D. A. Balaev, L.V. Kirensky Institute of Physics, Krasnoyarsk, 660036 Russia S. I. Popkov, L.V. Kirensky Institute of Physics, Krasnoyarsk, 660036 Russia S. V. Semenov, L.V. Kirensky Institute of Physics, Krasnoyarsk, 660036 Russia A. A. Bykov, L.V. Kirensky Institute of Physics, Krasnoyarsk, 660036 Russia E. I. Sabitova, Siberian Federal University, Krasnoyarsk, 660041 Russia A. A. Dubrovskiy, L.V. Kirensky Institute of Physics, Krasnoyarsk, 660036 Russia K. A. Shaikhutdinov, L.V. Kirensky Institute of Physics, Krasnoyarsk, 660036 Russia M. I. Petrov, L.V. Kirensky Institute of Physics, Krasnoyarsk, 660036 Russia Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    Cobalt manganese nanoceramics with nominal composition Co 1− x Mn x Fe 2 O 4 ( x =0.00, 0.15, 0.30, 0.45, 0.60, 0.75) were synthesized by a chemical coprecipitation technique. The X-ray diffraction patterns revealed the cubic spinel structure. The average crystallite size from the Sherrer formula was in the range of 28 nm–56 nm. The lattice parameter increased with a concentration of manganese. Scanning electron microscopy (SEM) was used for microstructural study. The electrical properties such as electrical resistivity ( ρ ), drift mobility ( μ d ), and activation energy (Δ E ) were measured using a two-probe apparatus in the temperature range 323–573 K. The electrical resistivity decreased with temperature and manganese concentration. The dielectric constant ( ε ′), loss factor or imaginary loss ( ε ″) and dielectric tangent loss (tan  δ ) were measured at room temperature using a LCR meter in the frequency range 100 Hz to 5 MHz. All the dielectric parameters decreased with increasing frequency. The AC electrical conductivity ( σ ac ) was calculated from the dielectric measurements. It increases with increase of frequency and manganese concentration. The increase in electrical conductivity may be attributed to the formation of Co +3 and Mn +3 from Co +2 and Mn +3 , respectively, at both A and B sites. Content Type Journal Article Pages 1-8 DOI 10.1007/s10948-011-1168-7 Authors Tasawar Javed, Thermal Transport laboratory, School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology (NUST) H-12, Islamabad, Pakistan Asghari Maqsood, Thermal Transport laboratory, School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology (NUST) H-12, Islamabad, Pakistan Akhlaq Ahmed Malik, Department of Metallurgical and Materials Engineering, University of Engineering and Technology (UET), Lahore, Pakistan Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    The influence of repulsion and attraction in high- T c superconductors to the gap functions is studied. A systematic method is proposed to compute the gap functions using the irreducible representations of the point group. It is found that a pure s -wave superconductivity exists only at very low temperatures, and attractive potentials on the near shells significantly expand the gap functions and increase significantly the critical temperature of superconductivity. A strong on-site repulsion drives the A 1 g gap into a B 1 g gap. It is expected that superconductivity with the A 1 g symmetry reaches a high critical temperature due to the cooperation of the on-site and the next-nearest neighbor attractions. Content Type Journal Article Pages 1-5 DOI 10.1007/s10948-011-1167-8 Authors W. LiMing, Dept. of Physics, and Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou, 510006 China Haibo Chen, Dept. of Physics, and Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou, 510006 China Liangbin Hu, Dept. of Physics, and Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou, 510006 China Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    The theoretical investigations of the superconducting state parameters (SSP) viz. electron-phonon coupling strength λ , Coulomb pseudopotential μ ∗ , transition temperature T C , isotope effect exponent α and effective interaction strength N O V of (Ni 33 Zr 67 ) 1− x M x (M=Ti,V,Co,Cu) ternary amorphous superconductors have been reported using Ashcroft’s empty core (EMC) model potential. Five different types of local field correction functions proposed by Hartree (H), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F) and Sarkar et al. (S) are used in the present investigation to study the screening influence on the aforesaid properties. The T C obtained from Sarkar et al. (S) local field correction function are found in excellent agreement with available theoretical data. Quadratic T C equation has been proposed, which provides successfully the T C values of ternary amorphous alloys under consideration. Also, the present results are found to be in qualitative agreement with other such earlier reported data, which confirms the superconducting phase in the superconductors. Content Type Journal Article Pages 1-11 DOI 10.1007/s10948-011-1170-0 Authors Aditya M. Vora, Humanities and Social Science Department, S.T.B.S. College of Diploma Engineering, Opp. Spinning Mill, Varachha Road, Surat, 395 006 Gujarat, India Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    Levitation forces of a high temperature superconductor (HTS) bulk with a different thickness over a permanent magnet railway (PMR) is studied mathematically. Several cylindrical models of HTS bulk with a diameter of 30 mm and a different thickness over a PMR are researched by the magnetic field vector method (H-method). A 3D-modeling numerical method using finite element method (FEM) is used to simulate the electromagnetic behavior of the models. The thickness of the HTS bulk increases with 1 mm from 4 mm to 15 mm. The simulation results show that the thickness of the HTS bulk and the minigap between the bottom surface of the bulk and the top surface of the PMR have much influence on the levitation forces. With a certain applied magnetic field, there is a certain thickness value of the bulk, which means the levitation force will not increase obviously with the increase of the thickness while the thickness larges the value. Content Type Journal Article Pages 1-4 DOI 10.1007/s10948-011-1154-0 Authors Yiyun Lu, Luoyang Institute of Science and Technology, Luoyang, Henan 471023, P.R. China Xucan Bai, Luoyang Institute of Science and Technology, Luoyang, Henan 471023, P.R. China Yunwang Ge, Luoyang Institute of Science and Technology, Luoyang, Henan 471023, P.R. China Jiasu Wang, Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu, Sichuan 610031, P.R. China Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    In this study, nanosize Silicon and Carbon (Si+C) were reacted with MgB 2 in order to enhance the critical current density. The polycrystalline bulks were synthesized by the direct in situ reaction method and their phase formation, crystal structure, and superconducting properties were evaluated. The enhanced relative peak intensity of Mg 2 Si and MgB 4 indicates the formation of a large volume fraction of these two phases with increasing (Si+C) additions. The a -axis lattice parameter shrinks significantly while c -axis increases slightly. The estimated C doping level at B site increases, leading to a degradation of the superconducting transition temperature with increasing (Si+C) additions. By a reaction with (Si+C), the field dependence of critical current density is shown to enhance at both 5 K and 20 K. Content Type Journal Article Pages 1-5 DOI 10.1007/s10948-011-1162-0 Authors K. Y. Tan, Department of Physics, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia K. L. Tan, Department of Physics, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia K. B. Tan, Department of Chemistry, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia K. P. Lim, Department of Physics, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia S. A. Halim, Department of Physics, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia S. K. Chen, Department of Physics, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    We report the effect of Zn Substitution on superconducting and normal state properties of new Y-based Y 3 Ba 5 Cu 8− x Zn x O 18− δ superconductor. The resistivity of the samples rather shows linear temperature dependence. Two cases of bipolaron model, in presence and absence of thermally excited individual polarons, are used to analyze normal state resistivity. The effect of Zn substitution on carrier localization, transition temperature, boson–boson relaxation time, and extended bosons are discussed. Content Type Journal Article Pages 1-6 DOI 10.1007/s10948-011-1190-9 Authors A. Esmaeili, Department of Physics, University of Urmia, P.O.B. 165, 11km Sero Road, Urmia, Iran H. Sedghi, Department of Physics, University of Urmia, P.O.B. 165, 11km Sero Road, Urmia, Iran M. M. Golzan, Department of Physics, University of Urmia, P.O.B. 165, 11km Sero Road, Urmia, Iran M. Amniat-Talab, Department of Physics, University of Urmia, P.O.B. 165, 11km Sero Road, Urmia, Iran Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    The magnetic properties of CoFe 2−2 x Cr 2 x O 4 spinels are studied by different theoretical methods: the mean field theory, the high-temperature series expansions (MFT, HTSE) and the probability distribution law with the different size L (nm). The exchange interactions and the critical temperature T c (K) are given for the nano-spinel ferrites. The magnetic phase diagram of CoFe 2−2 x Cr 2 x O 4 is deduced. The saturation magnetization, the coercivity field and magnetic energy are obtained. Content Type Journal Article Pages 1-4 DOI 10.1007/s10948-011-1189-2 Authors R. Masrour, LMPHE, Faculté des Sciences, Université Mohamed V, Rabat, Morocco M. Hamedoun, Institute for Nanomaterials and Nanotechnologies, Rabat, Morocco A. Benyoussef, LMPHE, Faculté des Sciences, Université Mohamed V, Rabat, Morocco Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    This work is related to the structural, superconducting, and transport properties of the compounds Y 3 Ba 5 Cu 8 O 18 and Y 3 Ba 5 Ca 2 Cu 8 O 18 prepared by the sol-gel method. The influence of the doping of Ca atoms into the compound Y 3 Ba 5 Cu 8 O 18 was studied by employing XRD, SEM, AFM, EDX, DTA, TGA, and the electrical resistivity ( ρ ), Hall coefficient ( R H ), Hall mobility ( μ H ), and magnetoresistance measurements. The XRD spectra showed that Y 3 Ba 5 Ca 2 Cu 8 O 18 almost has the same crystal structure as that of Y 3 Ba 5 Cu 8 O 18 , except with some impurity peaks. The resistivity measurements have pointed out that the compounds Y 3 Ba 5 Cu 8 O 18 and Y 3 Ba 5 Ca 2 Cu 8 O 18 have their T c -onset temperatures at approximately 92.7 and 86.6 K, respectively. The Hall coefficients R H and Hall mobilities μ H have been measured at the 10–300 K temperature interval in a magnetic field of 0.55 T. The signs of R H and μ H are found to be positive for both samples, which indicate that the conduction is p -type in our samples. As expected, the magnetoresistance results clearly demonstrate a considerable decrease of the offset temperatures with increasing magnetic field. Content Type Journal Article Pages 1-10 DOI 10.1007/s10948-011-1192-7 Authors Ali Osman Ayaş, Department of Physics, Faculty of Sciences and Letters, Adıyaman University, 02040 Adıyaman, Turkey Ahmet Ekicibil, Department of Physics, Faculty of Sciences and Letters, Cukurova University, 01330 Adana, Turkey Selda Kılıç Çetin, Department of Physics, Faculty of Sciences and Letters, Cukurova University, 01330 Adana, Turkey Atilla Coşkun, Department of Physics, Faculty of Sciences and Letters, Mugla University, 48000 Mugla, Turkey Ali Osman Er, Department of Physics, Old Dominion University, Norfolk, VA 23529, USA Yüksel Ufuktepe, Department of Physics, Faculty of Sciences and Letters, Cukurova University, 01330 Adana, Turkey Tezer Fırat, SNTG Laboratory, Physics Engineering Department, Hacettepe University, 06800 Ankara, Turkey Kerim Kıymaç, Department of Physics, Faculty of Sciences and Letters, Cukurova University, 01330 Adana, Turkey Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    Nominally pure and B 2 O 3 -added (Bi,Pb)-2223 HTS samples were synthesized in air on alumina plates. The influence of boron-doping as well as annealing conditions on the high- T c 2223 phase evolution was studied using X-ray diffraction (XRD), resistivity and AC susceptibility measurements. The B 2 O 3 -added samples with starting composition Bi 1.7 Pb 0.3 Ca 2 Sr 2 Cu 3 B x O y ( x =0.05 and 0.5) reveal significant enhancement of 2223 phase formation compared to the undoped sample. Higher-level boron doping x =1.5 leads to the degradation of high- T c 2223 phase. Content Type Journal Article Pages 1-4 DOI 10.1007/s10948-011-1196-3 Authors N. G. Margiani, Department of Coherent Optics and Electronics, V. Chavchanidze Institute of Cybernetics, Georgian Technical University, S. Euli str. 5, Tbilisi, 0186 Georgia I. R. Metskhvarishvili, Department of Physics, Faculty of Exact and Natural Sciences, Iv. Javakhishvili Tbilisi State University, Chavchavadze Ave. 3, Tbilisi, 0128 Georgia N. A. Papunashvili, Department of Coherent Optics and Electronics, V. Chavchanidze Institute of Cybernetics, Georgian Technical University, S. Euli str. 5, Tbilisi, 0186 Georgia D. I. Dzanashvili, Laboratory of Physicochemical Analysis, R. Agladze Institute of Inorganic Chemistry and Electrochemistry, Iv. Javakhishvili Tbilisi State University, Mindeli str. 11, Tbilisi, 0186 Georgia G. A. Shurgaia, Department of Coherent Optics and Electronics, V. Chavchanidze Institute of Cybernetics, Georgian Technical University, S. Euli str. 5, Tbilisi, 0186 Georgia Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    We show that the temperature-dependent resistivity ρ ( T ), Hall number n H ( T ) and the cotangent of the Hall angle cot  θ H ( T ) of Ba(Fe 1− x Co x )As 2 ( x =0.0–0.2) can be scaled using a recently proposed model-independent scaling method (Luo et al. in Phys. Rev. B 77:014529, 2008 ). The zero field normal-state resistivity above T c can be reproduced by the expresion and scaled using the energy scale Δ , c and the residual resistivity ρ 0 as scaling parameters. The scaling parameters have been calculated and the compositional variation of 2 Δ and ρ 0 has been determined. The 2 Δ ( x ) dependence show almost linear decreasing in underdoped regime, minimum corresponding to the T c maximum and increasing in overdoped regime. The latter is different from that reported for cuprates. The existence of a universal metallic ρ ( T ) curve which, however, is restricted for the underdoped compounds to temperatures above a structural and antiferromagnetic transition is interpreted as an indication of a single mechanism which dominates the scattering of the charge carriers in Ba(Fe 1− x Co x )As 2 ( x =0.0–0.2). Content Type Journal Article Pages 1-8 DOI 10.1007/s10948-011-1198-1 Authors E. Arushanov, Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden—IFW Dresden, 01069 Dresden, Germany S. Levcenko, Institute of Applied Physics, Academy of Sciences of Moldova, 2028 Chisinau, Moldova G. Fuchs, Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden—IFW Dresden, 01069 Dresden, Germany B. Holzapfel, Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden—IFW Dresden, 01069 Dresden, Germany S. L. Drechsler, Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden—IFW Dresden, 01069 Dresden, Germany L. Schultz, Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden—IFW Dresden, 01069 Dresden, Germany Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    A Monte Carlo study of the thermal variation of multilayers magnetization is carried out. We find a number of characteristics behaviors of the interface magnetization with its roughness. The spontaneous magnetization and magnetic susceptibility are calculated. It is found that multilayers magnetization decreases and phase transition temperature from ferromagnetic to paramagnetic varies with increasing interface thickness and concentration of nonmagnetic atoms in interface. Moreover, the susceptibility exhibits peaks at the transition temperature and it is interface morphology dependent. The dependence to the spin-exchange coupling is reported. Content Type Journal Article Pages 1-5 DOI 10.1007/s10948-011-1161-1 Authors A. Razouk, Laboratoire de Physique et Mécanique des Matériaux, Faculté des Sciences et Techniques, Université Sultan Moulay Slimane, BP 523, 23000 Béni Mellal, Morocco M. Sahlaoui, Laboratoire de Physique et Mécanique des Matériaux, Faculté des Sciences et Techniques, Université Sultan Moulay Slimane, BP 523, 23000 Béni Mellal, Morocco M. Sajieddine, Laboratoire de Physique et Mécanique des Matériaux, Faculté des Sciences et Techniques, Université Sultan Moulay Slimane, BP 523, 23000 Béni Mellal, Morocco Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    Bulk (MgB 2 ) 0.96 Ni 0.04 samples doping with premilled Ni powders were sintered at 750 °C for 30 min. During sintering, liquid Mg–Ni phase prompts solid–solid reaction between Mg and B and the size of milled Ni powder determines the final distribution of the secondary MgNi 2.5 B 2 phase in the sintered samples. A flux jump was observed in the (MgB 2 ) 0.96 Ni 0.04 samples doping with Ni powders. Recognized from the measured superconductive properties, smaller-sized Ni powders can provide more effective flux pinning centers and thus improve the performance of the critical current density. Content Type Journal Article Pages 1-5 DOI 10.1007/s10948-011-1160-2 Authors Qi Cai, Tianjin Key Lab of Composite and Functional Materials, School of Materials Science & Engineering, Tianjin University, Tianjin, 300072 P.R. China Zongqing Ma, Tianjin Key Lab of Composite and Functional Materials, School of Materials Science & Engineering, Tianjin University, Tianjin, 300072 P.R. China Qian Zhao, Tianjin Key Lab of Composite and Functional Materials, School of Materials Science & Engineering, Tianjin University, Tianjin, 300072 P.R. China Yongchang Liu, Tianjin Key Lab of Composite and Functional Materials, School of Materials Science & Engineering, Tianjin University, Tianjin, 300072 P.R. China Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    We present a theory of superconductivity based on the theoretical prediction that a macroscopic persistent current is generated by spin-vortices. It explains the origin of the phase variable θ that is canonical conjugate to the superfluid density as a Berry phase arising from the spin-vortex formation. This superconductivity does not require Cooper-pairs as charge carriers, thus, is not directly related to the standard theory based on the BCS one; however, it exhibits the flux quantization in the unit Φ 0 = hc /2| e |, where h is Planck’s constant, c the speed of light, and e the electron charge; and the AC Josephson frequency, f J =2| e | V / h , where V is the voltage of the battery connected to the superconductor–insulator–superconductor junction. In due course, it is found that the standard derivation of the AC Josephson frequency misses a term arising from the flow of particles through the leads connected to the junction. If this contribution is included, the observed f J indicates that the phase θ is a variable conjugate to the number density of charge e carriers instead of the currently accepted charge 2 e carriers. We propose an experiment that discriminates whether it is e or 2 e . If the above claim is verified, it means that the BCS theory cannot predict whether a particular compound is a superconductor or not since it does not explain the origin of θ . A connection between the present mechanism and the BCS mechanism is discussed; the fact that the BCS theory gives an excellent estimate of T c is attributed to the fact that it predicts the temperature at which spin-vortices become long-lived due to the energy gap formation; since the stabilization by the electron-pair formation is compatible with the present mechanism, asymmetries observed in the even and odd number of electron systems are preserved. The most notable difference is that the persistent current generation is formulated in a strictly particle-number-conserving manner. Thus, it does not violate the superselection rule for the total charge. Content Type Journal Article Pages 1-15 DOI 10.1007/s10948-011-1159-8 Authors Hiroyasu Koizumi, Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    The magnetization and the initial susceptibility have been calculated for a one-dimensional linear chain structured dilute ferrofluid considering nearest neighbor magnetic interaction for N -particles. The initial susceptibility is calculated as a function of the orientation angle between the field and the chain direction. Our results predict Curie–Weiss behavior for a one-dimensional magnetic fluid, and showed that the ordering temperature T 0 depends on the particles separation in a very complicated way. This more general case of calculation reduces to simple results found by the Dimer and Trimer models when N equals 2 and 3, respectively. Content Type Journal Article Pages 1-6 DOI 10.1007/s10948-011-1144-2 Authors Abdalla A. Obeidat, Department of Physics, Jordan University of Science & Technology, Irbid, Jordan 22110 Maen A. Gharaibeh, Department of Physics, Jordan University of Science & Technology, Irbid, Jordan 22110 Dia H. Al Samarh, Department of Physics, Jordan University of Science & Technology, Irbid, Jordan 22110 Mohammad H. Qaseer, Department of Physics, Jordan University of Science & Technology, Irbid, Jordan 22110 Nabil Y. Ayoub, School of Applied Natural Sciences, German Jordanian University, Amman, Jordan Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939

Description:    Zn 0.98 Cu 0.02 O films have been prepared under different conditions by pulsed laser deposition. Ferromagnetism with saturate magnetization of about 7 emu/cm 3 at 300 K has been observed in Zn 0.98 Cu 0.02 O film prepared in N plasma at room temperature. The concentration of oxygen vacancies was increased by N substituting O in N plasma, and the ferromagnetism originated from the aligned magnetic moments of more Cu ions mediated by oxygen vacancies. Furthermore, ferroelectricity has been confirmed by the observation of the electrical field dependent converse piezoelectric coefficient d 33 loop at room temperature, indicating the potential multiferroic applications. Content Type Journal Article Pages 1-4 DOI 10.1007/s10948-011-1164-y Authors Qingyu Xu, Department of Physics, Southeast University, Nanjing, 211189 China Hao Liu, Department of Physics, Southeast University, Nanjing, 211189 China Zheng Wen, Department of Materials Science and Engineering, Nanjing University, Nanjing, 210008 China Jinlong Gao, Department of Physics, Nanjing University, Nanjing, 210008 China Di Wu, Department of Materials Science and Engineering, Nanjing University, Nanjing, 210008 China Qi Li, Department of Physics, Southeast University, Nanjing, 211189 China Shaolong Tang, Department of Physics, Nanjing University, Nanjing, 210008 China Mingxiang Xu, Department of Physics, Southeast University, Nanjing, 211189 China Journal Journal of Superconductivity and Novel Magnetism Online ISSN 1557-1947 Print ISSN 1557-1939