1 4 A ug 1 99 8 Coexistence of localized and itinerant carriers near T C in calcium - doped manganites ?
نویسندگان
چکیده
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 the coexistence of field-and temperature-dependent polaronic and band-electron fractions conducting in parallel. To test the validity of this model, we apply it to the thermoelectric coefficient using the well-known Nordheim-Gorter rule for parallel conducting channels. 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.
منابع مشابه
Ja n 19 99 Coexistence of localized and itinerant carriers near T C in calcium - doped manganites
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, a...
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