La_(0.5)Sm_(0.2)Sr_(0.3)MnO_3/x(Sb_2O_3)体系电输运性质及MR温度稳定性  

ELECTRICAL TRANSPORT PROPERTY AND TEMPERATURE STABILITY OF MR OF La_(0.5)Sm_(0.2)Sr_(0.3)MnO_3/x(Sb_2O_3) SYSTEM

作　　者：刘鹏[1,2] 严国清[1,2] 唐永刚[1,2] 王桂英[1,2] 彭振生[1] 

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),安徽宿州234000 [2]宿州学院机械与电子工程学院,安徽宿州234000

出　　处：《低温物理学报》2013年第1期30-33,共4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);安徽省教育厅自然科学研究项目(批准号:KJ2012Z404);自旋电子与纳米材料安徽省重点实验室培育基地开放课题(2012YKF09、2011YKF08)资助的课题~~

摘　　要：用固相反应法制备La0.5Sm0.2Sr0.3MnO3/x(Sb2O3)(x=0.00,0.02,0.04,0.05,0.075,0.10,0.15)系列样品,通过X射线衍射(XRD)谱、电阻率-温度(ρ～T)曲线、ρ～T拟合曲线、磁电阻-温度(MR～T)曲线,研究了该体系的电输运性质及MR的温度稳定性.所有样品的电输运性质都表现出绝缘体-金属相变,相变温度很高(312K)且基本保持不变,随Sb2O3复合量增大,电阻率迅速增大,类金属导电可以用ρ=ρ0+AT2公式拟合,表明导电机制是电子-电子相互作用,x=0.075的样品,在200～320K温区磁电阻基本保持不变,MR的温度稳定性是晶界引起的隧穿磁电阻与钙钛矿颗粒体相本征磁电阻竞争的结果.First, the sample series of La0. 5Smo.2Sr0.2MnO3/x （Sb2O3）（ x=0. 00,0. 02,0. 04,0.05,0. 075,0. 10, 0. 15） were prepared by thesolid-state reaction method, then, X-ray diffraction （XRD） spectra, resistivity-tempera- ture （ρ-T） curves, puT fitted curves, and magnetoresistance-temperature （MR-T） curves were utilized to research the electrical transport property and temperature stability of MR. All the samples in this research undergo the insulator-metal phase transition with a high and basically stable transition temperature （312 K）, and with the in-crease of Sb2 03 amount, the resistivity increases rapidly. The metal-like conduction can be fitted by the formulaρ= ρ0 ＋ATe , which shows that the conduction mechanism arises from the electron-electron interaction. MR of the sample of x=0. 075 basically keeps the same in the temperature range of 200-320 K. The temperature stability of MR is the result of the competition between tunneling MR induced by grain boundary and intrinsic MR of body phase of perovskite grains.

关 键 词：磁电阻温度稳定性 电输运性 二相复合体 钙钛矿锰氧化物 

分 类 号：O614.331[理学—无机化学]