High-pressure x-ray diffraction and Raman spectra study of indium oxide

High-pressure synchrotron radiation x-ray diffraction and Raman spectroscopy measurements of indium oxide (In2O3) were carried out at room temperature up to 27.8 and 26.2 GPa, respectively. A pressure-induced phase transition from cubic-phase (Ia (3) over bar) was observed at a pressure above 12.8-15.3 GPa, which disagrees with earlier theoretical prediction (3.8 GPa). According to the x-ray diffraction experimental data, the high-pressure phase is isostructural with hexagonal corundum-type structure (R3 (3) over bar symmetry). However, broad peaks observed in Raman spectra suggest that the high-pressure structure is disordered. The volume change from cubic phase to corundum phase is about 4% and the axial ratio c/a in the corundum phase decreases with increasing pressure. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.2999369]