用化学镀法制备的铜包覆La_(0.7)Ca_(0.3)MnO_3复合体系的巨磁电阻效应  

GIANT MAGNETORESISTANCE IN La_(0.7)Ca_(0.3)MnO_3 COATED BY COPPER USING ELECTROLESS METHOD

作　　者：宋书建[1] 张炯[1] 熊永红[1] 皮厚礼[1] 任忠明[1] 包西昌[1] 熊曹水[1] 

机构地区：[1]华中科技大学物理系,武汉430074

出　　处：《低温物理学报》2006年第4期316-320,共5页Low Temperature Physical Letters

基　　金：国家自然科学基金(项目编号:10274022)资助的课题.~~

摘　　要：用化学镀法制备了铜包覆的La_(0.7)Ca_(0.3)MnO_3(LCMO)颗粒.这些粉末压片之后在氩气中煅烧,形成铁磁-金属型结构,得到被铜均匀包覆的LCMO复合材料.利用扫描电子显微镜(SEM)观察了LCMO被铜包覆的形貌.研究了不同烧结温度下样品的电输运性质和在0.3T外加磁场下的磁电阻行为.结果表明LCMO在通过包覆铜进行表面修饰后,样品的绝缘体-金属的转变温度(Tp)往高温移动接近室温,室温附近的磁电阻值也得到显著提高.The La0.7 Ca0.3 MnO3 （LCMO） powders coated by copper have been successfully prepared by an eleetroless method. After these powders were palletized and sintered at different temperature in argon, a ferromagnet-metal type composite, LCMO-Cu, have been fabricated. Temperature dependence resistivity and magnetoresistanee in the applied field of 0.30 T were studied. It is absorbing that the metal-insulator transition temperature （Tp） approximately go up to 280 K after surface finish.

关 键 词：复合材料 磁电阻(MR) 边界效应 

分 类 号：O482.5[理学—固体物理]