ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Doping effects arising from Fe and Ge for Mn in La0.7Ca0.3MnO3 (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 2998-3000 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Structural, magnetic, and transport properties of polycrystalline La0.7Ca0.3Mn1−xFexO3 and La0.7Ca0.3Mn1−xGexO3 are experimentally studied. Single-phase samples are obtained in the range x=0–0.12 for Fe, and x=0–0.06 for Ge. There are no appreciable structure changes due to the introduction of Fe and Ge. The Mn-site doping favors a reduced magnetic/resistive transition, at rates of ∼22 K for 1% Fe and ∼28 K for 1% Ge, and an elevated resistivity. No metal–insulator transition occurs when the content of Fe exceeds ∼0.1. The enhanced doping effects in La0.7Ca0.3Mn1−xGexO3 can be ascribed to the reduced hole concentration noting that the presence of Fe and Ge influence the contents of mobile eg electrons and holes in the compounds, respectively. Equivalence of the effects from Fe and Ge doping, respectively, to those due to eg electron and hole trapping and the relation between Mn- and O-site doping are discussed. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.122656
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Spin-state transition in La1−xSmxCoO3 perovskites (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 1331-1335 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Structural and magnetic properties of La1−xSmxCoO3 with x=0, 0.02, 0.04, 0.06, 0.08, 0.12, 0.16, and 0.2 have been systematically studied. LaCoO3 exhibits a rhombohedral structure of R3¯C symmetry. The lattice parameters decrease progressively with the incorporation of Sm, and a second orthorhombic phase of Pbnm symmetry appears for x≥0.12. The volume fraction of the orthorhombic phase is a sensitive function of the Sm content in the compounds, and increases from 16% for x=0.12 to 75% for x=0.2. Accordingly, the low-spin-to-high-spin transition of the trivalent Co ions, characterized by a steep rise of the magnetization, shifts to higher temperatures. A molecular field analysis indicates an increased energy gap, from 317 K for x=0 to 500 K for x=0.2, between the low-spin and the high-spin state, implying a stabilization of the low-spin trivalent Co ions by the presence of Sm. The enhanced compressive chemical pressure due to the introduction of Sm is suggested to be responsible for the present observations. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1336521
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Structural and magnetoresistive properties of La0.7Ca0.3Mn0.96(Al1−xInx)0.04O3 (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 3619-3622 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Structural, magnetic, and transport properties of ABO3-type La0.7Ca0.3Mn0.96(Al1−xInx)0.04O3 are investigated. Different structure deformation from that in the A-site doping, characterized by the synchronous variation of the lattice constants b with c/(square root of 2) versus the content of In in the compounds, is observed. The metal–semiconductor transition shows a strong In content dependence. The transition temperature decreases monotonously from 180.7 to 103.4 K as x varies from 0 to 1, with a corresponding maximum resistivity ranging from 2.9 to 410.8 Ω cm. The magnetoresistive properties of the materials are strongly affected by the size mismatch between A- and B-site ions, and a relation similar to that presented by Hwang et al. [Phys. Rev. Lett. 75, 914 (1995)] is observed though controlling of the tolerance factor, is realized by B-site doping. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.369723
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Oxygen content dependence of the transport property of La2/3Sr1/3CoO3−δ film (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 2831-2835 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Effects of oxygen content on the resistivity of epitaxial (110)La2/3Sr1/3CoO3−δ film have been experimentally studied. The oxygen release, measured by the change of lattice parameter, was controlled by annealing the film at different temperatures in vacuum. Significant oxygen loss can take place at temperature as low as ∼200 °C. A quantitative relation between resistivity ρ and oxygen deficiency δ was established. For δ〈0.07, a linear decrease of the resistive transition temperature with δ was found. The temperature dependence of the low temperature resistivity follows ρ∝T2 for δ〈0.046, and ρ∝exp[(T0/T)1/2] for 0.067〈δ〈0.16. A transition from T1/2 variable-range hopping to T1/4 variable-range hopping takes place for δ〉0.17, which may be a result of the absence of Co4+ which are the nuclei of metallic clusters. Compared to La1−xSrxCoO3 with similar Co4+ content, the resistivity of the La2/3Sr1/3CoO3−δ film is significantly low, which may be the consequence of a larger quantity of Sr in the film. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1390500
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Magnetic and transport behaviors of La0.5(Sr0.53Ca0.47)0.5MnO3 under pressure, magnetic field, and Fe doping (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 3139-3144 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Effects of pressure, magnetic field, and Mn-site doping on the magnetic structure and resistive behavior of La0.5(Sr0.53Ca0.47)0.5Mn1−xFexO3 (0≤x≤0.10) have been experimentally studied. The system experiences two magnetic transitions subsequently with decreasing temperature: a paramagnetic to ferromagnetic transition and a ferromagnetic to antiferromagnetic (AFM) transition. The second magnetic transition coincides with a steep resistivity jump. In addition to reducing the critical temperature for the AFM transition (TN), the incorporation of Fe enhances the ferromagnetic order below TN as demonstrated by the gradual increase of magnetization with the content of Fe. Long-range AFM order is replaced by short-range AFM order when x exceeds 0.03, and disappears completely for x〉0.06. The application of pressure or magnetic field depresses the AFM nature of the compounds, resulting in a downward shift of TN at a rate of ∼7 K/GPa or ∼4 K/T. The most interesting observation of the present study is the greatly enhanced resistivity jump at TN, which increase from 1 to 2 orders, after the sample undergoes a pressurizing and then a pressure relieving process. Although high pressure, magnetic field, and Fe doping produce similar effects on the AFM order, the underlying physics is different. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1446228
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    State switching in Bi-doped La0.67Ca0.33MnO3 and the effects of current (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 81 (2002), S. 508-510 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electronic transport and magnetic properties of La0.477Bi0.193Ca0.33MnO3 have been experimentally studied. Different resistive behaviors are observed in the cooling and warming processes. The system first stays at a high resistive state, and switches to a state of lower resistivity when it is cooled below a critical temperature. However, keeping the sample at a temperature below ∼60 K, a relaxation to the high resistive state takes place. This process is current dependent, and the application of a large current slows down the relaxation greatly. There is a strong competition between the two resistive states, which causes a switch of the system between states. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1494109
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Strain-dependent vacuum annealing effects in La0.67Ca0.33MnO3−δ films (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 1164-1166 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of vacuum annealing on the structural and transport properties of the La0.67Ca0.33MnO3−δ films grown on SrTiO3 (LCMO/STO) and NdGaO3 (LCMO/NGO) substrates have been studied. A lattice expansion due to oxygen release during the annealing is observed. Under the same condition, the change of the out-of-plane lattice parameter in LCMO/STO is two to three times larger than that in LCMO/NGO, indicating a strong tendency for the oxygen in the former to escape. Correspondingly, the metal-to-semiconductor transition shifts to lower temperatures, linearly with lattice constant until a critical value, Δd=0.03 Å for LCMO/STO and Δd=0.05 Å for LCMO/NGO, after which a sudden drop of the transition temperature to zero occurs. The different lattice strains in both films are presumably responsible for the different critical oxygen contents for the occurrence of the resistive transition. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.125971
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Enhanced low-field magnetoresistance in La2/3Ca1/3MnO3/Pr2/3Ca1/3MnO3 superlattices (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 80 (2002), S. 628-630 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on the observation of enhanced low-field magnetoresistance in La2/3Ca1/3MnO3/Pr2/3Ca1/3MnO3 (LCMO/PCMO) superlattices with ultrathin PCMO layers. In particular, [LCMO(100 Å)/PCMO(10 Å)]17 superlattice exhibits magnetoresistance MR=Δρ/ρ0=−55% in a magnetic field of 500 Oe and at temperature 219 K. The enhancement is associated with the ultrasharp metal–insulator transition. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1445802
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Surface spin-glass behavior in La2/3Sr1/3MnO3 nanoparticles (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 3863-3865 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The low-temperature magnetic and transport properties of La2/3Sr1/3MnO3 nanoparticles have been investigated. It is found that a surface spin-glass behavior exists in La2/3Sr1/3MnO3 nanoparticles, which undergo a magnetic transition to a frozen state below 45 K. The low-temperature surface spin-glass behavior exists even at the highest field used (H=50 kOe). Moreover, the spin-glass-like transition disappears for particles above 50 nm. In addition, the suppressed low-field magnetoconductivity (LFMC) observed at low temperature for nanosized La2/3Sr1/3MnO3 is obviously lower than the expected upper limit of LFMC, 1/3, for polycrystalline manganites, which is proposed to arise from the higher-order tunneling through the insulating spin-glass-like surface layers. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1379597
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Comment I on "Grain-boundary effects on the electrical resistivity and the ferromagnetic transition temperature of La0.8Ca0.2MnO3" [Appl. Phys. Lett. 77, 118 (2000)] (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 1790-1791 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1350645
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...