La1-x(Sr1-yKy)xMnO3的电输运性质及磁电阻的温度稳定性  

Electric Transport Property and Temperature Stability of Magnetoresistance of La_(1-x)(Sr_(1-y)K_y)_xMnO_3

作　　者：王闻琦[1] 严国清[1] 杨杰[1] 王桂英[1] 唐永刚[1] 宋启祥[1] 张明玉[1] 彭振生[1,2] 

机构地区：[1]自旋电子与纳米材料安徽省重点实验室培育基地,宿州学院机械与电子工程学院,安徽宿州234000 [2]中国科学技术大学,合肥微尺度物质科学国家实验室,合肥230026

出　　处：《硅酸盐学报》2011年第12期1958-1962,共5页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金重点(19934003);安徽省教育厅自然科学研究重点(KJ2011A259);宿州学院教授(博士)基金(2011jb01,2011jb02)及宿州学院科研平台开放课题(2011YKF07)资助项目

摘　　要：用固相反应法制备La1-x(Sr1-yKy)xMnO3(x=0.2～0.1,y=0.0,0.2,0.4,0.6,0.8,1.0)系列样品,通过X射线衍射谱,电阻率-温度曲线,磁电阻-温度曲线,研究在A位同时掺入1价、2价元素而保持摩尔比n(Mn3+)/n(Mn4+)不变的La1-x(Sr1-yKy)xMnO3体系的电输运性质及磁电阻的温度稳定性。结果表明:在高温区,电阻率出现反常系A位离子的无序度及磁不均匀性对双交换作用所致;电阻率-温度曲线出现的双峰现象系表面相电阻率与体相电阻率竞争的结果;在251～177K,y=0.8样品的磁电阻从8.2%缓慢上升到9.4%,磁电阻的温度稳定性有利于磁电阻的实际应用。Polycrystalline samples of La1-x（Sr1-yKy）xMnO3（x=0.2～0.1,y=0.0,0.2,0.4,0.6,0.8,1.0） were prepared by solid-state reaction method. Electric transport property and temperature stability of magnetoresistance of the samples with unchanged mole ratio n（Mn3＋）/n（Mn4＋） through the introduction of both univalent and bivalent elements at A-site were studied by X-ray diffraction, resis- tivity–temperature （ρ–T） curves and magnetoresistance–temperature curves analysis. Results show that abnormal resistivity in high temperature range has been observed due to the influence of disorder and magnetic inhomogeneity of A-site ions on double-exchange function, and the double peaks in ρ–T curves are ascribed to the competition between surface resistivity and body resistivity. Magne- toresistance of the sample with y=0.8 ascends slowly from 8.2% to 9.4% from 251 K to177 K, and the temperature stability of mag- netoresistance favors its practical application of magnetoresistance.

关 键 词：磁电阻 温度稳定性 电输运性质 晶界效应 磁不均匀性 

分 类 号：O482.54[一般工业技术—材料科学与工程]