钙钛矿材料La_(0.65)Ca_(0.35)Mn_(1-x)Fe_xO_3的低场磁电阻特性探讨

Investigation of the low-field magnetoresistance behavior for perovskite materials La_(0.65)Ca_(0.35)Mn_(1-x) Fe_xO_3

我们制备了氧化物材料La0 .6 5 Ca0 .35 Mn1-xFexO3(x =0、0 .0 1、0 .0 2、0 .0 3) ,研究了材料在低场 0 .57T下的磁电阻效应。我们发现氧化物材料La0 .6 5 Ca0 .35 Mn1-xFexO3的居里温度Tc 及电阻峰位温度TP 均随铁含量的增加而下降 ,这主要是因为Fe离子不参加双交换作用 ,且阻挡了双交换作用的进行 ,材料的铁磁作用随铁含量增加而减弱。利用迪尼模型计算了La0 .6 5 Ca0 .35Mn1-xFexO3材料在零场及磁场为 0 .57T下电阻随温度的变化关系 。

In the present work, the perovskite oxides La 0.65 Ca 0.35 Mn 1- x Fe x O 3( x =0,0.01,0.02,0.03) were prepared. The magnetoresistance effect under low field of 0.57T has been investigated. The Curie temperature T c and the transition temperature of metal/semiconductor T P decreases with increasing Fe content, since Fe ion does not participate but hinders the double exchange interaction. The ferromagnetic interaction decreases with increasing Fe content in La 0.65 Ca 0.35 Mn 1- x Fe x O 3. Based on the Dionne model we calculated the temperature dependences of the resistance under fields of H =0 and H =0.57T, respectively. The calculated results agree to the experimental data quite well.