Investigations of anharmonic effects via phonon mode variations in nanocrystalline Dy2O3, Gd2O3 and Y2O3

Abstract

The nanocrystalline rare earth sesquioxides Dy2O3, Gd2O3 and Y2O3 have been investigated for anharmonic effects in the temperature range 80-440K using Raman spectroscopy. These samples were cubic in structure under ambient conditions with particle sizes in nano-range. The predominant T-g+A(g) phonon modes of the samples primarily exhibited phonon softening in the investigated temperature range. However, the line width variations clearly reflected the variations in the effects of anharmonicity on these samples, and the related anharmonic constants were estimated. The mode Grueneisen parameters required for these studies were deduced from our own high-pressure data for these samples reported earlier. The line width variations for these samples were found to display similar trends; however, their magnitudes were indicative of the factors that are expected to contribute to the variation in phonon behaviour