High-pressure study of Cr2O3 obtained by high-temperature oxidation by X-ray diffraction and Raman spectroscopy

A high-pressure study of a scale of Cr2O3, prepared by oxidation of chromium in oxygen at 1173 K, was performed at room temperature in a diamond anvil cell. Both X-ray diffraction and Raman spectroscopy were used to follow the high-pressure behaviour of this oxide. Cr2O3 undergoes a slight structural deformation at a pressure of about 13 GPa, indicated by a change in the Raman spectrum, and the possibility of a magnetic contribution is discussed. No particular features are observed by X-ray diffraction. X-ray diffraction results show that the compressibility of chromium oxide can be considered as isotropic in the pressure range of 0-25 GPa, and validates the use of pressure dependence of Raman modes for determination of stresses in thin films of chromia. Volume compressibility obtained by X-ray diffraction data is equal to 3.86(7)x10(-12) and 3.0(1)x 10(-12) Pa-1 from Raman data. (C) 2001 Elsevier Science Ltd. All rights reserved.