Phase stability of some rare earth trihydrides under high pressure

Investigations of the phase stability of erbium and gadolinium trihydrides have been performed using argon as pressure transmitting medium in Raman scattering method. The same medium has been used for X-ray diffraction analysis under pressure for erbium trihydride. Significant difference in the transition pressure as compared to earlier results obtained in quasi hydrostatic conditions has been noticed both in X-ray and Raman scattering measurements. Deviatoric stresses present in earlier nonhydrostatic measurements can be blamed for its discrepancy.