Hugoniot measurement of alumina (Al2O3) single crystal in the pressure range up to over 100 GPa

A high-pressure phase transition of Al2O3 from the corundum structure to the Rh2O3(II) structure at over 70 GPa has been theoretically predicted, while sufficient experimental evidences have not been reported. In this study, the Hugoniot-measurement experiments were performed on a corundum-structure Al2O3 single crystal to obtain the informations about the high-pressure polymorph. The Hugoniot parameters were measured by the inclined-mirror method in the pressure range up to over 100 GPa. A possible kink due to phase transition was observed on the inclined-mirror images in the pressure range higher than 70 GPa.