La_(0.5)Ba_(0.5)CoO_3中Y的替代效应  

Substituting Effect of Yttrium in La_(0.5)Ba_(0.5)CoO_3

作　　者：刘宜华[1] 张汝贞[1] 王成建[1] 岳龙强[1] 季刚[1] 梅良模[1] 

机构地区：[1]山东大学物理学院,山东济南250100

出　　处：《中国稀土学报》2002年第3期244-247,共4页Journal of the Chinese Society of Rare Earths

基　　金：国家重点基础研究专项经费 (G19980 613 0 10 );国家科技部资助项目

摘　　要：用固相反应法制备了La0 .5-xYxBa0 .5CoO3多晶材料 ,系统研究了Y的替代对材料磁性和输运特性的影响 ,结果发现 ,Y的掺入主要产生了两种效应 ,一是Y向Co的 3d轨道产生了电荷转移 ,使分子磁矩下降 ,二是出现了Co离子的反铁磁交换作用 ,当Y含量少于或等于 0 .3时 ,材料中出现了自旋的非共线结构。当Y含量大于 0 .3时 ,材料从铁磁态为主转变为反铁磁态为主。对不同Y含量的材料 ,其导电机制都属于极化子的变程跳跃导电 ,随Y含量增加 ,材料电阻率迅速增大。La 0.5- x Y xBa 0.5 CoO 3 polycrystals were prepared by the solid state reaction. Substituting effects of Y for La on the magnetic and transport properties of the materials were studied systematically. The results indicate that substitution of Y induces two effects. Firstly, the charge transfer from Y to 3d orbital of Co happens. This causes the molecular magnetic moment to decrease. Secondly, the antiferromagnetic exchange interaction of Co ions appears. When the content of Y is less or equal to 0.3, the non co linear structure of spins in materials is observed. When the content of Y is greater than 0.3, the materials transit from mainly ferromagnetic state to mainly antiferromagnetic one. The conductive mechanism for the materials with different content of Y belongs to the variable range hopping conduction of polarons. The resistivity of materials increases sharply with increasing Y content.

关 键 词：La0.5Ba0.5CoO3 替代效应 稀土 电荷转移 自旋非共线结构 变程跳跃导电 钴酸钡镧 半导体 钇 

分 类 号：TN304.3[电子电信—物理电子学]