Pressure-induced amorphization of A-site-deficient double perovskite Ln1/3MO3 (Ln = Pr, Nd, M = Nb, Ta)

摘要: High-pressure X-ray diffraction measurements have demonstrated that the cation-deficient perovskites Pr1/3NbO3, Pr1/3TaO3, Nd1/3NbO3, and Nd1/3TaO3 undergo irreversible pressure-induced amorphization (PIA). This occurs near 14.5 GPa for niobates 18.5 GPa tantalates. The unit cell volumes of four oxides show an almost linear decrease as pressure is increased. It concluded PIA transition at higher pressures in tantalates due to lower MO6 initial tilting ambient conditions, which associated with larger atomic mass tantalum. behavior these compared CaTiO3, role both weakening M–O–M π-bonding cation vacancies on observed structural changes discussed.