(1-x)La_(2/3)Ca_(1/3)MnO_3/xSb_2O_5复合体系的电子输运和磁电阻行为

Electrical Transport Behavior and Magnetoresistance Properties of (1-x)La_(2/3)Ca_(1/3)MnO_3/xSb_2O_5 Composites

用两步法制备了(1-x)La2／3Ca1／3MnO3／xSb2O5复合样品．零场下电阻温度关系测量表明,对x<3％范围,随Sb2O5含量增加,复合样品电阻率增大,绝缘体-金属转变温度降低;而对x>3％范围,随Sb2O5含量增加,复合样品电阻率减小,绝缘体-金属转变温度提高．磁电阻测量表明,少量Sb2O5同La2／3Ca1／3MnO3复合,可明显增强磁电阻效应．

The composites with the nominal composition of （1 - x）La2/3Cal/3MnO3/xSb2O5 were fa ricated. The study of temperature dependence of resistivity at zero field shows that the metal-insulator transition temperature （Tp） and the resistivity of the composites are dependent on Sb2O5 addition level x. When x 〈3%, Tp shifts towards low temperature and resistivity increases with the increase of x. But Tp shifts towards high temperature and resistivity decreases with further increasing of x. The measurement for temperature dependence of magnetoresistance （MR） indicates that MR effect can be largely enhanced in the composites with small Sb2O5 addition.