In situ high-pressure synchrotron x-ray diffraction study of CeVO4 and TbVO4 up to 50 GPa

TL;DR

This study investigates the high-pressure structural phase transitions of CeVO4 and TbVO4 using synchrotron x-ray diffraction up to 50 GPa, revealing multiple phase changes and their reversibility, with implications for understanding their compressibility and structural behavior.

Contribution

First in situ high-pressure x-ray diffraction analysis of CeVO4 and TbVO4 up to 50 GPa, detailing their phase transitions and compressibility properties.

Findings

TbVO4 undergoes a non-reversible zircon to scheelite transition at 6.4 GPa.

TbVO4 exhibits a reversible scheelite to M-fergusonite transition at 33.9 GPa.

CeVO4 shows an irreversible zircon to monazite transition at 5.6 GPa and a reversible monazite to orthorhombic transition at 14.7 GPa.

Abstract

Room temperature angle-dispersive x-ray diffraction measurements on zircon-type TbVO4 and CeVO4 were performed in a diamond-anvil cell up to 50 GPa using neon as pressure-transmitting medium. In TbVO4 we found at 6.4 GPa evidence of a non-reversible pressure-induced structural phase transition from zircon to a scheelite-type structure. A second transition to an M-fergusonite-type structure was found at 33.9 GPa, which is reversible. Zircon-type CeVO4 exhibits two pressure-induced transitions. First an irreversible transition to a monazite-type structure at 5.6 GPa and second at 14.7 GPa a reversible transition to an orthorhombic structure. No additional phase transitions or evidences of chemical decomposition are found in the experiments. The equations of state and axial compressibility for the different phases are also determined. Finally, the sequence of structural transitions and the compressibilities are discussed in comparison with other orhtovanadates and the influence of non-hydrostaticity commented.