High-pressure phase transitions and pressure-induced amorphization in LiVO3

Lithium metavanadate (LiVO3) single crystals have been studied by Raman spectroscopy under high pressure up to 200 kbar. Three phase transitions were observed and they are believed to be a series of transitions involving the breaking up of the infinite VO4- chains into VO3- ions of average symmetry C3 nu . On decompression, the LiVO3 transforms into an amorphous phase instead of reverting to the ambient crystalline phase, similarly to what has been observed for alpha -NaVO3. The difference in the behaviours between LiVO3 and alpha -NaVO3 on compression has been explained by the different sizes of the Li+ and Na+ ions. The restoration of the virgin crystalline phase and the relinking of the VO4- chains were observed after heating the reclaimed samples.