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中国物理学会期刊

La1-xTexMnO3晶格结构的X射线粉末衍射分析

CSTR: 32037.14.aps.56.1702

XRD analysis on lattice structure of La1-xTexMnO3

CSTR: 32037.14.aps.56.1702
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  • 通过X射线粉末衍射数据,用Rietveld精修方法分析了Te部分替换LaMnO3中La后,其晶格参数及其结构对称性所发生的变化.结果表明:Te掺杂LaMnO3系列样品具有R3C的晶格结构对称性,其MnO6八面体晶格还产生了伸张畸变,畸变程度随Te掺杂量的增加而增大.此外根据Mn—O—Mn键角、eg电子能带的带宽、A位离子平均半径及A位离子尺寸失配度等的变化特点,推测Te掺杂LaMnO3样品除居里温度等相变物理量将随x增加而非线性变化外,还可能产生自旋玻璃态、相分离等宏观现象.

     

    Based on X-ray powder diffraction data, the lattice structure and symmetry of La1-xTexMnO3 (0.04≤x≤0.2) have been analyzed by Rietveld refining method. the results show that all samples structure have a rhombohedral symmetry with space group R3C, and the lattice of MnO6 octahedron has a stretching distortion due to the difference in cation size. Besides, the degrec of structure distortion is closely related to Te content and can be depicted with the following three factors: the Mn—O—Mn bond angle θMn—O—Mn, the average A-site radius 〈rA〉 and the A-site sizemismatch σ2. According to the changing trend of these factors, several conjecture on physical properties are discussed, including the Curie temperature, spin-glass and phase separation etc.

     

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