Observation of charge ordering by Raman scattering inNd0.5Ca0.5MnO3 thin films

Abstract

We report on the first observation by Raman scattering of charge ordering in thin films ofNd0.5Ca0.5MnO3. We observe the emergence of additional phonon excitations at low temperature that confirmsthe structural transition accompanying the charge ordering. The properties of our defect-freeNd0.5Ca0.5MnO3 thin films are very similar to those of the single crystals. Thisbehaviour appears to be different from previous Raman reports onPr0.5Ca0.5MnO3 and La0.5Ca0.5MnO3 thin films. We speculate that the different growth conditions, in particular our highersubstrate temperature, are responsible for such a difference.