Hydrostatic compression of four corundumhyphen;type compounds: agr;hyphen;Al2O3, V2O3, Cr2O3, and agr;hyphen;Fe2O3

摘要

Accurate xhyphen;ray diffraction experiments for hydrostatic compression of corundum agr;hyphen;Al2O3and transitionhyphen;metal sesquioxides with the corundum structure, V2O3, Cr2O3, and agr;hyphen;Fe2O3, were performed using a cubichyphen;anvil type of highhyphen;pressure apparatus at room temperature up to about 120 kbar. An isotropic compression of the unit cell was found in agr;hyphen;Al2O3and Cr2O3. In V2O3and agr;hyphen;Fe2O3, anisotropic behaviors of compression were observed: The ratioc/ain the hexagonal cell increases in V2O3and decreases in agr;hyphen;Fe2O3with increasing pressure. The isothermal bulk modulusKT=1.75plusmn;0.03 Mbar of V2O3is unusually small among the studied compounds with the corundum structure. Values of 2.39plusmn;0.04 Mbar and 2.31plusmn;0.05 Mbar were calculated forKTof agr;hyphen;Al2O3and Cr2O3, and a value of 2.31plusmn;0.10 Mbar forKTof agr;hyphen;Fe2O3in the pressure range below 30 kbar.