Structure change of pyrochlore Sm2Ti2O7 at high pressures

Structural evolution of pyrochlore titanate Sm2Ti2O7 at high pressures was investigated by in situ Raman and x-ray diffraction methods. An intermediate phase was found at high pressures. The structure is a distorted pyrochlore, where anions are disordered after 40GPa while the cations are still somewhat ordered up to 51GPa. When the pyrochlore structure is severely distorted by external pressure, it transforms completely to an amorphous phase quenchable to room conditions.