Phase transitions in Lu2O3 under high pressure

Pressure induced phase transitions in Lu2O3 at 298 K have been investigated using angular-dispersive X-ray diffraction (ADXRD), Raman spectroscopy and X-ray absorption near edge structure (XANES) techniques under quasi-hydrostatic high pressures up to 39.5, 31.0 and 20.0 GPa, respectively. In situ ADXRD measurements found that the transition from the cubic to monoclinic phase began at about 17.0 GPa and completed at 21.4 GPa by a ∼7.8% volume decrease. The fitting of volume compression data to the third-order Birch–Murnaghan equation of state yielded that the zero-pressure isothermal bulk moduli and the first-pressure derivatives were 113.5 ± 0.7 GPa and 1.7 ± 0.3 for the cubic phase, respectively. In situ Raman measurements had similar finding. Lu LIILII-edge XANES measurements suggested pressure induced enhancement of the occupation of Lu 5d bands.