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首页> 外文期刊>Solid State Communications >Structural, magnetic and magnetotransport behavior of some Nd-based perovskite manganites
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Structural, magnetic and magnetotransport behavior of some Nd-based perovskite manganites

机译：某些钕基钙钛矿锰矿的结构，磁和磁输运行为

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A systematic investigation of Neodymium based colossal magnetoresistive manganites with general formula Nd_(0.67)A_(0.33-)MnO_3, (A = Ca, Sr, Pb and Ba) has been undertaken mainly to understand their structural, magnetic as well as electrical behavior. The materials were prepared by the sol-gel route sintering at 900℃. After usual characterization of the materials structurally by XRD, their metal-insulator transition (T_P) as well as magnetic transition (T_C) temperatures were determined and the reasons for the occurrence of ΔT_T(T_C-T_P) values have been explained. X-ray data have been analyzed by using Rietveld analysis and the variations of various parameters are explained. It has been concluded that not only A-site cation radius, < r_A > but also the size variance factor (σ~2) influence both the metal-insulator as well as ferro to para magnetic transition temperatures. A systematic study of electrical conductivity of all the four materials was undertaken as a function of magnetic field upto 7 T mainly to understand the conduction mechanism in the presence of magnetic field. On analyzing the electrical resistivity data, it has been concluded that the metallic (ferromagnetic) part of the resistivity (ρ) (below T_P) can be explained by electron-electron scattering processes ( ～ T~2) and two magnon scattering processes ( ～ T~(4.5)), while in the high temperature (T > T_P) paramagnetic insulating regime, the adiabatic small polaron and variable range hopping models are found to fit well.
机译：系统地研究了通式为Nd_（0.67）A_（0.33-）MnO_3（A = Ca，Sr，Pb和Ba）的钕基巨大磁阻锰矿，主要是为了了解它们的结构，磁学和电学行为。该材料是在900℃下通过溶胶-凝胶法烧结制备的。在通过XRD对材料进行常规表征后，确定了它们的金属-绝缘体转变（T_P）和磁转变（T_C）温度，并解释了发生ΔT_T（T_C-T_P）值的原因。使用Rietveld分析对X射线数据进行了分析，并解释了各种参数的变化。已经得出结论，不仅A位阳离子半径，而且尺寸方差因子（σ〜2）都影响金属绝缘体以及铁磁至顺磁转变温度。进行了对这四种材料的电导率的系统研究，该电导率是直到7 T的磁场的函数，主要是为了了解存在磁场时的传导机理。通过分析电阻率数据，可以得出结论，电阻率（ρ）（低于T_P）的金属（铁磁）部分可以通过电子-电子散射过程（〜T〜2）和两个磁子散射过程（〜 T〜（4.5）），而在高温（T> T_P）顺磁绝缘状态下，绝热小极化子和可变范围跳跃模型非常适合。

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