六方类钙钛矿体系La_2Ca_2MnO_7-Sm_2Ca_2MnO_7的结构变化和相关系  

Structure Variation and Phase Relationship of the Hexagonal Perovskite System La_2Ca_2MnO_7-Sm_2Ca_2MnO_7

作　　者：别利剑[1,2] 李国宝[1] 廖复辉[1] 林建华[1] 

机构地区：[1]北京大学化学与分子工程学院,稀土材料化学与应用国家重点实验室,北京100871 [2]临沂师范学院化学系,临沂276005

出　　处：《高等学校化学学报》2003年第5期753-756,共4页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:20131010)

摘　　要：利用柠檬酸盐前驱物法制备了La_(2-x)Sm_xCa_2MnO_7系列样品,并利用Rietveld方法对结构进行了精修.结果表明,体系中存在两个单相区(x≤0.8和x≥1.0)和一个两相区(O.8<x<1.0).体系的这种结构变化可以用稀土离子的半径变化说明.La2-xSmxCa2MnO7 samples were prepared from citric acid sol-gel precursor by using solid state reaction. The cell parameters of the sample were refined by using Rietveld method, which evidence the presence of single-phase regions(x≤0. 8 and x≥1. 0) and two-phase region 0. 8<x<1. 0. The structure variation of the system can be understood by considering the ionic size of rare earth cation.

关 键 词：六方类钙钛矿 夹层化合物 锰酸盐 固体化学 稀土 柠檬酸盐前驱物法 结构 相变 

分 类 号：O614.33[理学—无机化学]