High-pressure study of Cr 2O 3 obtained by high-temperature oxidation by X-ray diffraction and Raman spectroscopy

Abstract

A high-pressure study of a scale of Cr 2O 3, 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. Cr 2O 3 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)×10 −12 and 3.0(1)×10 −12 Pa −1 from Raman data.