La_(0.5)Ca_(0.5)MnO_3中Ca位上Ba掺杂效应研究  

Ba-Doping Effect on Ca Sites of La_(0.5)Ca_(0.5)MnO_3

作　　者：姜勇[1] 李广[2] 曾祥勇[1] 汤萍[2] 孙霞[2] 黄真[2] 袁松柳[1] 

机构地区：[1]华中理工大学物理系,武汉430074 [2]中国科学院等离子体物理研究所,合肥230031

出　　处：《无机材料学报》2000年第3期531-535,共5页Journal of Inorganic Materials

基　　金：中国科学院九五重点基金!KJ952-J1-417

摘　　要：用固态反应法制备了具有单相结构的La0.5Ca0.5-xBaxMnO3系列样品，其结构随Ba含量增加由立方晶系转变为典型的正交晶系．零场下输运性质实验表明，在较低掺杂量时，系统在整个温区显示半导体型导电特征，而当掺杂量超过0.14时，系统发生由半导体到金属的转变，且转变的温度随掺杂量增加而移向高温瑞．基于对实验结果的分析，就Ca位上Ba掺杂所起的作用进行了初步探讨．Single-phase polycrystalline samples of La0.5Ca0.5-xBa.MnO3 (0.15≤x≤0.5) were fabricated by the solid state reaction method. With increasing the content of Ba doping, the structural transition occurs from cubic to orthorhombic. The measurement of resistance as a function of temperature under zero field shows that the samples of lower doping behave a semiconducting behavior in the whole studied temper ature range, and a transition from semiconducting to metallic states appears in the samples x≥0.14. The transition moves toward the high temperature region with increasing the doping content. The role of Ba doping on the Ca sites was discussed on the basis of analyzing the experimental data.

关 键 词：超大磁电阻效应 钙位 钡 掺杂效应 

分 类 号：TM271.01[一般工业技术—材料科学与工程]