Photoluminescence and phase transition in Er2O3 under high pressure

Abstract The phase transitions of Er 2 O 3 were investigated using angular dispersive synchrotron x-ray diffraction (AD-XRD) and photoluminescence (PL) spectroscopy at high pressure in different pressure transmitting media. Two successive structural transformations were revealed upon compression. The structural transformation from a cubic Ia -3 to a monoclinic C 2/ m structure started at 13.6 GPa, and the hexagonal P -3 m 1 phase began to appear at approximately 17.8 GPa in helium. Compared with the data in helium, Er 2 O 3 showed a much lower onset pressure (6.6 GPa) of the cubic-monoclinic phase transition in silicon oil. The bulk modulus of the cubic phase was obtained from the compression data. The PL measurement indicated that the luminescence lines belonging to the transition of 2 H 11/2  →  4 I 15/2 and 4 S 3/2  →  4 I 15/2 of Er 2 O 3 were modified under high pressure, which was closely related to the structural phase transition.