La位Dy^(3+)的替代对(La_(1-x)Dy_x)_(0.67)Ca_(0.33)MnO_3传输性质的影响

Influence of Dy^(3+) Substitution for La on transport properties in (La_(1-x)Dy_x)_(0.67)Ca_(0.33)MnO_3

在La0.67Ca0.33MnO3中用Dy对La进行了部分替代,随替代量增加,材料的居里温度和金属-绝缘体相变温度单调下降,峰值电阻率单调增加,磁电阻比急剧增大。这些变化可以用稀土离子平均直径的减小和自旋团簇模型来解释。Dy掺杂引起的磁结构变化将导致CMR效应。

The Dy substituting effects for La in La0.67 Ca0.33 MnO3 has been investigated. With increasing substituting amount of Dy, the Curie temperature Tc, the metal - insulator phase transition temperature Tp for the samples decrease monotonically while the peak resistivity and the corresponding CMR effect increases dramatically. These changes can be explained in terms of the decrease in average diameter of rare - earth ions and the model of spin clusters. The disordered spin clusters are induced in the samples due to the Dy doping. The variation in magnetic structure caused by Dy doping leads to colossal magnetoresistance.