Pressure-induced amorphization of La(1/3)NbO3

La(1/3)NbO(3), an A-site cation deficient double perovskite, has been studied under pressure by synchrotron X-ray powder diffraction and Raman spectroscopy. In contrast to other highly distorted perovskites, transforming to post-perovskite on compression, La(1/3)NbO(3) undergoes irreversible pressure induced amorphization at similar to 14.5 GPa. Over a wide range of pressure before that transition it presents an almost linear volume decrease versus pressure, accompanied by convergence form orthorhombic to a cubic unit cell. The Raman spectroscopy also shows an amorphization at the same pressure. However, where upon full decompression the X-ray diffraction pattern remains amorphous, new Raman peaks become active. (C) 2011 Elsevier B.V. All rights reserved