【摘要】 实验研究了两个典型掺杂的La1-xCaxMnO3(x =0 .3和x =0 .6)样品的热导率与电导率随温度的变化关系 ,测量温区为 77～ 30 0K .样品的热导率与电导率的温度曲线之间有着很大的相似性 :在高温部分 ,两个样品的电导率均随温度降低而下降 ,热导率也呈现类似的温度关系 ;在低温部分 ,两个样品的电导率呈现相反的温度关系 ,热导率的变化也截然不同 .而且 ,在La1-xCaxMnO3多晶材料中 ,电导率很小 ,使得电子直接贡献的热导部分微乎其微 .分析指出 ,La1-xCaxMnO3巨磁阻材料中由Jahn Teller效应引起的晶格畸变 ,受到电子状态的直接影响和制约 ,从而对热导产生不同的作用 .更多还原

【Abstract】 The temperature dependence of the thermal conductivity κ(T) and electrical conductivity κ(T) in La-{1-x}Ca-xMnO-3 polycrystals was measured from 77K to 300K for two samples (x=0.3 and x=0.6). In the whole temperature range, the curves of σ(T) and κ(T) are very similar for each sample. Furthermore, the magnitude of electrical conductivity is so small in this kind of polycrystalline samples that the electronic contribution to thermal conductivity is little. We suppose that the local lattice distortions tuned up by the state of electrons play the key role in the thermal conductivity of La-{1-x}Ca-xMnO-3 polycrystals.更多还原