Pr_(0.45)(Ca_(1-x)Sr_x)_(0.55)MnO_3体系调带宽引起的磁相变及电输运性质转变  

MAGNETIC PHASE TRANSITION AND TRANSPORT PROPERTY TRANSITION INDUCED BY BANDWIDTH ADJUSTING IN Pr_(0.45)(Ca_(1-x)Sr_x)_(0.55)MnO_3 SYSTEM

作　　者：唐永刚[1,2] 王桂英[1,2] 毛强[1,2] 叶吾梅[1,2] 彭振生 

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234000 [2]宿州学院机械与电子工程学院,宿州234000

出　　处：《低温物理学报》2011年第6期415-421,共7页Low Temperature Physical Letters

基　　金：国家自然科学基金重点项目(批准号:19934003);安徽省教育厅自然科学研究重点项目(批准号:KJ2011A259;KJ2009A53Z);安徽省教育厅自然科学研究项目(批准号:KJ2009B281Z);自旋电子与纳米材料安徽省重点实验室培育基地(批准号:2010YKF04)资助的课题~~

摘　　要：采用固相法制备了Pr0.45(Ca1-xSrx)0.55MnO3(x=0.0,0.2,0.4,0.6,0.8,1.0)多晶样品.通过测量样品的X射线衍射(XRD)谱、磁化强度-温度(M～T)曲线、电阻率-温度(ρ～T)曲线,研究了Sr2+替代Ca2+对Pr0.45Ca0.55MnO3体系磁性和电性的影响.实验发现:随带宽增大,磁性增强,电荷有序相逐渐减弱并最终融化;与磁测量相对应,电荷有序融化后,电阻率突降了几个数量级;电荷有序态体系导电机制是可变程跃迁,电荷有序破坏后转为小极化子绝热跃迁.体系在极低温41K附近发生自旋玻璃转变.The polycrystalline samples of Pr0.45（Ca1-xSrx）0.55MnO3 （x=0. 0, 0. 2, 0. 4, 0. 6, 0. 8, 1.0） are prepared by solid-state reaction. Influence of Sr^2＋ substitution for Ca^2＋ at A site on transport properties and magnetic properties is studied through the measurements of X-ray diffraction （XRD） spectrum, the magnetization -temperature （M-T） curves and the resistivity-temperature （ρ-T） curves. The results show that the magnetism strength- ens, and charge ordering becomes weaker and it is melted completely at last with the increasing of bandwidth. The resistivity decreases by, several orders of magnitude suddenly after the melting of charge-ordering （CO） phase, which is corresponding to magnetism. The conductive mechanism of charge-ordering （CO） phase system is the variablerange hopping of charge carriers, and it becomes the small polaron adiabatic transport behavior after the melting of charge-ordering （CO） phase. The spin-glass behavior appears at about 41K.

关 键 词：调带宽 电荷有序相 磁相变 电输运性质 

分 类 号：O482.5[理学—固体物理]