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Suppression of Ferromagnetic Double Exchange by Vibronic Phase Segregation

F. Rivadulla·M. Otero-Leal·A. Espinosa·A. de Andres·C. Ramos·J. Rivas·J. B. Goodenough
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Abstract

From Raman spectroscopy, magnetization, and thermal-expansion on the system La2/3(Ca1-xSrx)1/3MnO3, we have been able to provide a quantitative basis for the heterogeneous electronic model for manganites exhibiting colossal magnetoresistance (CMR). We construct a mean-field model that accounts quantitatively for the measured deviation of TC(x) from the TC predicted by de Gennes double exchange in the adiabatic approximation, and predicts the occurrence of a first order transition for a strong coupling regime, in accordance with the experiments. The existence of a temperature interval TC<T<T* where CMR may be found is discussed, in connection with the occurrence of an idealized Griffiths phase.

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F. Rivadulla, M. Otero-Leal, A. Espinosa, A. de Andres, C. Ramos, J. Rivas, J. B. Goodenough. 2005-11-29. Suppression of Ferromagnetic Double Exchange by Vibronic Phase Segregation. https://doi.org/10.1103/physrevlett.96.016402

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