La_(2/3)Ca_(1/3)MnO_3/TE(TE=Cu、Fe、Zn)复合颗粒系统的磁输运行为比较性研究  

A COMPARATIVE STUDY OF TRANSPORT PROPERTIES OF La_(2/3)Ca_(1/3)MnO_3/TE(TE=Cu、Fe、Zn) COMPOSITE GRANULAR SYSTEM

作　　者：刘莉[1] 缪菊红[1] 肖循[1] 余功奇[1] 任光明[1] 王永强[1] 李派[1] 田召明[1] 

机构地区：[1]华中科技大学物理系,武汉430074

出　　处：《低温物理学报》2007年第1期46-51,共6页Low Temperature Physical Letters

基　　金：国家自然科学基金(项目编号:10374032;10574049)~~

摘　　要：用化学方法制备出La2／3Ca1／3MnO3／TE（TE=Cu、Fe和Zn）复合颗粒系统，并通过零场和外加低磁场（0.3T）下电阻率（P）随温度（T）变化关系测量对这些复合系统的输运和低场磁电阻行为进行了比较性研究．相对于纯La2／3Ca1/3MnO3颗粒系统，Cu引入后，绝缘体-金属转变温度（TIM）降低，P减小，P（T）曲线表现出明显的热滞豫现象，磁电阻（MR）在转变温度附近表现出峰行为且峰值处的MR值高达-35％．引入Fe后，TIM升高，电阻率减小，但MR随T降低而单调增加，引入Zn后，TIM降低，P增加，在TIM附近也出现MR峰但峰值较小，同时，也注意到，在含Fe和Zn的系统中都没有观察到明显的热滞豫现象．La2/3Ca1/3MnO3/TE（TE=Cu、Fe、Zn） composite granular systems were prepared in a chemical route, and a comparative study of their transport and low field magnetoresistance （MR） properties was performed by measuring the temperature （T） dependence of resistivity （p） in zero field and a applied field of 0.3 T. When Cu was introduced, the insulator-metal transition temperature （ TIM ） moves to lower temperature, p decreases, p（T） curve shows distinct heat hysteresis, MR shows a peak near TIM and the peak value is -35%. When Fe were introduced, TIM moves to higher temperature, p decreases, but MR increases with temperature decreasing. When Zn were introduced, TXM moves to lower temperature, p increases, near TIM MR peak also appears, but its value is smaller than that in the composite system containing Cu. In the composite system containing Fe and Zn, no distinct heat hysteresis was observed.

关 键 词：输运性质 低场磁电阻 自旋 

分 类 号：O482.5[理学—固体物理]