La_(0.5)Sm_(0.2)Sr_(0.3)MnO_3/Ag_x二相复合体的结构及磁电阻  

Structure and Magnetoresistance of La_(0.5)Sm_(0.2)Sr_(0.3)MnO_3/Ag_x Two-Phase Composite

作　　者：王桂英[1] 彭振生[1,2] 唐永刚[1] 刘鹏[1] 牛晓飞[1] 

机构地区：[1]宿州学院自旋电子与纳米材料安徽省重点实验室,安徽宿州234000 [2]中国科学技术大学结构分析重点实验室,安徽合肥230026

出　　处：《稀有金属》2010年第2期210-214,共5页Chinese Journal of Rare Metals

基　　金：国家自然科学基金重点项目(19934003);安徽省教育厅自然科学研究重大项目(ZD2007003-1);安徽省教育厅自然科学研究项目(KJ2008A34ZC;KJ2009A053Z);安徽省教育厅自然科学研究项目(KJ2009B281Z)资助

摘　　要：用固相反应法制备La0.5Sm0.2Sr0.3MnO3/(Ag2O)x/2(x=0.00,0.04,0.08,0.25,0.30)样品,通过X射线衍射谱线(XRD),扫描电子显微镜(SEM)照片及SEM能谱(EDS),ρ-T曲线,研究样品的输运行为及磁电阻效应。结果表明:少量掺杂时Ag全部挥发。掺杂量较多时,挥发后多余的Ag主要以金属态包覆在母体颗粒的表面,使体系形成两相复合体。掺Ag为30%摩尔比时,样品的电阻率较低掺杂样品的电阻率降低一个数量级,在300K、0.5T磁场下,磁电阻明显增强,达到9.4%,这与颗粒母体界面结构的改善有关,也与材料电阻率的降低有关。La0.5Sm0.2Sr0.3MnO3/(Ag2O)x/2(x=0.00,0.04,0.08,0.25,0.30)samples were prepared using the solid-state reaction method,and their transport behavior and magnetoresistance effect were studied through X-ray diffraction(XRD),scanning electron microscope(SEM)photos,energy dispersion spectrum(EDS)of SEM and ρ-T curves.The results showed that:Ag volatilized completely when the doping amount was small.Ag was mainly distributed at the grain boundary of the mother body and was in metallic state when the doping amount w...

关 键 词：室温低场磁电阻 晶界磁电阻 二相复合体 钙钛矿锰氧化物 

分 类 号：O482.5[理学—固体物理]