Rietveld fitting of x-ray diffraction spectra for the double phase composites La0.7−xSr0.3Mn1−yO3−1.5(x+y)/(Mn3O4)y/3
Rietveld fitting of x-ray diffraction spectra for the double phase composites La0.7−xSr0.3Mn1−yO3−1.5(x+y)/(Mn3O4)y/3
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DOI：
10.1063/1.3054355
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发表时间：
2009-01
影响因子：
3.2
通讯作者：
S. P. Liu;G. Tang;P. Hao;L. Q. Xu;Y. G. Zhang;W. Qi;X. Zhao;D. Hou;Wei Chen
中科院分区：
文献类型：
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作者：
S. P. Liu;G. Tang;P. Hao;L. Q. Xu;Y. G. Zhang;W. Qi;X. Zhao;D. Hou;Wei Chen
采用溶胶-凝胶法制备了La0.7−xSr0.3MnO3锰氧化物样品，研究了镧的缺乏对样品结构和磁性的影响。X射线衍射（XRD）谱表明，当x≤0.05时，材料为R3 <$c钙钛矿结构的单相;当x≥0.10时，材料为R3 <$c钙钛矿为主相，Mn 3 O 4为第二相的两相。使用XRD分析，这些材料可以表示为La0.7−xSr0.3Mn1− yO 3 −1.5（x+y）/（Mn 3 O 4）y/3。根据晶体缺陷的热平衡理论，计算了ABO 3钙钛矿相中A、B和O位的离子比。这些离子比率用于XRD光谱的Rietveld拟合。发现居里温度TC对B位Mn 4+离子含量比RM 4的依赖性与典型钙钛矿La 1 − xSrxMnO 3相似。
The effects of lanthanum deficiency on the structural and magnetic properties of manganites with normal composition La0.7−xSr0.3MnO3 prepared by the sol-gel method with the highest heat treatment temperature at 800 °C have been investigated. X-ray diffraction (XRD) spectra indicate that the materials possess a single phase with the R3¯c perovskite structure for x≤0.05, and that they possess two phases with the R3¯c perovskite being the dominant phase and Mn3O4 being the second phase for x≥0.10. Using XRD analysis, these materials can be expressed as La0.7−xSr0.3Mn1−yO3−1.5(x+y)/(Mn3O4)y/3. On the basis of the thermal equilibrium theory of crystal defects, the ion ratios at the A, B, and O sites in the ABO3 perovskite phase were calculated. Those ion ratios were used in Rietveld fitting of the XRD spectra. It was found that the dependence of the Curie temperature TC on the content ratio RM4 of Mn4+ ions at B site is similar to that of the typical perovskite La1−xSrxMnO3.