用Dy和Yb部分替代La0 67Ca0.33MnO3中的La使材料的居里温度单调下降.掺Dy使材料的相变温度单调下降,峰值电阻率迅速增大,磁电阻比急剧增大.掺入13%(原子分数)的Dy可使材料的最大磁电阻比增大近40倍而掺Yb对磁电阻的影响要小得多.用自旋团簇理论可以解释庞磁电阻的形成.
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