La-Gd-Ca-Mn-O的不可逆磁电阻效应  

IRREVERSIBLE MAGNETORESISTANCE EFFECT IN La-Gd-Ca-Mn-O

作　　者：刘宜华[1] 张汝贞[1] 王成建[1] 岳龙强[1] 奕开政 梅良模[1] 黄佶[2] 

机构地区：[1]山东大学物理系,济南市250100 [2]山东大学实验中心

出　　处：《材料研究学报》2001年第5期540-544,共5页Chinese Journal of Materials Research

基　　金：国家重点基础研究专项经费G19980613010;国家科技部经费资助项目

摘　　要：随掺 Ｇｄ量的增加．Ｌａ－Ｇｄ—Ｃａ－Ｍｎ－Ｏ化合物的金属－绝缘体相变温度逐渐下降，对应的 峰值电阻率大幅度增加，磁电阻比明显提高，掺入 １１％的 Ｇｄ可以使材料的磁电阻比提高一个数量级． Ｇｄ的掺入还引起材料磁电阻出现明显的不可逆效应，随掺Ｇｄ量增加。The doping effects of Gd in La-Ca-Mn-O compound were studied. It was found that the metal-insulator transition temperature decreased monotonously, the corresponding peak resistivity increased dramatically, the magnetoresistance ratio increased significantly with increasing the doping amount of Gd. The substitution of 11% Gd for La in La-Ca-Mn-O improved the magnetoresistance ratio by an order of magnitude. An irreversible effect of magnetoresistance was found in the Gd doped samples. This effect was enhanced with increasing Gd doping amount remarkably. It can be ascribed to a field-induced irreversible transition to metallic state.

关 键 词：稀土锰氧化物 巨磁电阻效应 不可逆磁电阻效应 磁电阻 导电性 

分 类 号：O482.5[理学—固体物理] TM27[理学—物理]