High-pressure powder x-ray diffraction study of EuVO4

TL;DR

This study investigates the high-pressure structural transformations of EuVO4 using synchrotron x-ray diffraction, revealing phase transitions, stability ranges, and partial decomposition up to 34.7 GPa, with detailed structural refinements and EOS analysis.

Contribution

It provides new high-pressure data on EuVO4, including phase transition pressures, structural stability, and decomposition behavior, extending previous experimental pressure ranges.

Findings

Zircon-scheelite transition at 6.8 GPa

Scheelite-fergusonite transition at 23.4 GPa

Fergusonite remains stable up to 34.7 GPa

Abstract

The high-pressure structural behavior of europium orthovanadate has been studied using in-situ, synchrotron based, high-pressure x-ray powder diffraction technique. Angle-dispersive x-ray diffraction measurements were carried out at room temperature up to 34.7 GPa using a diamond-anvil cell, extending the pressure range reported in previous experiments. We confirmed the occurrence of zircon-scheelite phase transition at 6.8 GPa and the coexistence of low- and high-pressure phases up to 10.1 GPa. In addition, clear evidence of a scheelite-fregusonite transition is found at 23.4 GPa. The fergusonite structure remains stable up to 34.7 GPa, the highest pressure reached in the present measurements. A partial decomposition of EuVO4 was also observed from 8.1 to 12.8 GPa, however, this fact did not preclude the identification of the different crystal structures of EuVO4. The crystal structures of the different phases have been Rietveld refined and their equations of state (EOS) have been determined. The results are compared with the previous experimental data and theoretical calculations.