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Revealing polarons with high pressure on low electron-doped manganites

G. Garbarino·C. Acha·D. Vega·G. Leyva·G. Polla·C. Martin·A. Maignan·B. Raveau
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Abstract

Pressure sensitivity (up to 1 GPa) of the electrical resistivity and of the ac susceptibility was measured for low electron doping levels of Ca$_{1-x}$Y$_x$MnO$_3$ (CYMO) and of Ca$_{1-x}$Sm$_x$MnO$_3$ (CSMO) ceramic samples (0.05 $\leq$ x $\leq$ 0.15). A very weak pressure dependence of the Curie temperature (T$_c$) was observed for both systems ($\sim$ 6 K GPa$^{-1}$), when compared to the hole-doped manganites of the same T$_c$ ($\sim$ 20 K GPa$^{-1}$). Our results can be interpreted within a modified Double Exchange scenario, where pressure alters the reduction of the bandwidth produced by the electron-phonon interaction associated with small Fröhlich polarons in the weak to intermediate coupling regime.

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G. Garbarino, C. Acha, D. Vega, G. Leyva, G. Polla, C. Martin, A. Maignan, B. Raveau. 2003-10-02. Revealing polarons with high pressure on low electron-doped manganites. https://doi.org/10.1103/physrevb.70.014414

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