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

M. Jaime·P. Lin·S. H. Chun·M. B. Salamon·P. Dorsey·M. Rubinstein
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Abstract

We explore the possibility that polaronic distortions in the paramagnetic phase of La$_{0.67}$Ca$_{0.33}$MnO$_3$ 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.

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M. Jaime, P. Lin, S. H. Chun, M. B. Salamon, P. Dorsey, M. Rubinstein. 1999-01-26. Coexistence of localized and itinerant carriers near Tc in calcium-doped manganites. https://doi.org/10.1103/physrevb.60.1028

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