LaB_(0.5)Mn_(0.5)O_3(B=Co,Fe)的磁性及电输运特性的研究  

THE MAGNETIC AND TRANSPORT PROPERTIES OF LaB_(0.5)Mn_(0.5)O_3 (B=Co,Fe)

作　　者：刘宝琴[1] 刘振华[1] 任世超[1] 刘丽君[1] 张春伟[1] 何军辉[1] 

机构地区：[1]扬州大学物理科学与技术学院,扬州225002

出　　处：《低温物理学报》2011年第2期146-150,共5页Low Temperature Physical Letters

摘　　要：采用固相烧结工艺制备了钙钛矿锰氧化物LaCo0.5Mn0.5O3和LaFe0.5Mn0.5O3,系统研究了样品的磁性、电输运特性和磁电阻效应.室温下LaCo0.5Mn0.5O3和LaFe0.5Mn0.5O3均呈现顺磁行为.电子顺磁共振得到LaFe0.5Mn0.5O3样品的朗德因子g=1.9661,与Fe3+离子(g=2)很接近,因此可以得出Fe在样品中主要呈正三价.从ρ(T)曲线可以看出样品均呈现半导体特性,对其进行拟合后,曲线遵循电荷输运的可变程跃迁(VRH)模型.由样品的MR(T)曲线可以看出B位Fe和Co的不同取代,对样品的磁电阻特性有一定的影响,LaCo0.5Mn0.5O3表现出较大的低温MR效应.LaCo0.5Mn0.5O3 and LaFe0.5Mn0.5O3 have been prepared by traditional solid-state reaction method.The magnetic,transport properties and magnetoresistance have been systematically investigated.Both of the samples are paramagnetic at room temperature.From the room temperature Electron Spin Resonance（ESR） we get the Lande factor of LaFe0.5Mn0.5O3 （g=1.9661）.Both of the samples are semiconductors,at temperatures from 300 to 140K,T-1/4 （T is temperature） dependence of the conductivity was found to meet Mott variable-range hopping model.The different ions of B site have significant effect on the magntoresistance.At low temperature,LaCo0.5Mn0.5O3 shows well magnetoresistance effect.

关 键 词：钙钛矿锰化物 磁性 电子顺磁共振 磁电特性 磁电阻特性 

分 类 号：O482.5[理学—固体物理]