La_(5/8-x)Pr_xCa_(3/8)MnO_3体系电输运特性的研究  

STUDY OF ELECTRICAL TRANSPORT FOR La_(5/8-x)Pr_xCa_(3/8)MnO_3 SYSTEM

作　　者：杨聚刚[1] 敬超[1] 曹桂新[1] 杨勇[1] 曹世勋[1] 张金仓[1] 

机构地区：[1]上海大学物理系,上海200444

出　　处：《低温物理学报》2005年第A01期486-492,共7页Low Temperature Physical Letters

基　　金：国家自然科学基金(No.10274049);上海市科委基础研究重点项目(No.04JC14039);上海市教委曙光计划(No.03SG35);上海市教委重点学科建设项目的资助~~

摘　　要：对La5/8-xPrxCa3/8MnO3(x=0,0.13,0.20,0.25)体系的电输运特性进行了系统研究.结果表明随着Pr含量的增大金属-绝缘转变温度(TMI)减小,在高于TMI的温度区域,该体系的电输运行为具有绝缘体特性,符合可变程跳跃模型;而在较低温度(50K以下),其电阻率存在极小值现象,且随磁场的增大而逐渐受到抑制.对这种电阻率极小值现象从强电子-电子相互作用角度进行了分析讨论.In this paper, electrical transport properties of polycrystalline La5/8-xPrxCa3/8MnO3 （x= 0, 0.13,0. 20,0.25） have been investigated systematically. The measurements indicate that the Metal-insulator transition TMI shifts to lower temperature with the increasing doping of Pr content. Electrical transport properties at higher temperature can be explained quite well according to the variable-range-hopping （VRH） theory. While the behavior of resistivity minima appears at low-temperature for all of the samples. Resistivity minima are depressed gradually with the increasing magnitude of applied magnetic field. This phenomenon is analyzed according to the enhanced electron-electron interactions.

关 键 词：La5/8-xPrxCa3/8MnO3 电阻极小值现象 磁电阻 

分 类 号：O511.4[理学—低温物理]