Coexistence of localized and itinerant carriers near T-C in calcium-doped manganites

Article

关键词: COLOSSAL-MAGNETORESISTANCE;    FERROMAGNETIC TRANSITION;    POLARON CROSSOVER;    PEROVSKITE;    LA1-XCAXMNO3;    RESISTIVITY;    TRANSPORT;    LA0.67CA0.33MNO3;    LA2/3CA1/3MNO3;    LA1-XSRXMNO3;   

DOI  :  10.1103/PhysRevB.60.1028

来源: SCIE

【 摘 要 】

We explore the possibility that polaronic distortions in the paramagnetic phase of La0.67Ca0.33MnO3 manganites persist in the ferromagnetic phase by considering the observed electrical resistivity to arise from coexisting field- and temperature-dependent polaronic and band-electron fractions. We use an effective medium approach to compute the total resistivity of the two-component system, and find that a limit with low percolation threshold explains the data rather well. To test the validity of this model, we apply it to the thermoelectric coefficient. We propose a plausible mean-field model that reproduces the essential features of a microscopic model and provides a comparison with the experimental mixing fraction, as well as the magnetization and magnetic susceptibility.

【 授权许可】

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