High-Pressure Single-Crystal X-Ray Diffraction Study of ErVO₄

Area of Science:

• Solid-state chemistry
• Materials science
• Crystallography

Background:

• Understanding the high-pressure behavior of rare-earth vanadates is crucial for materials science.
• Erbium vanadate (ErVO4) is a material with potential applications influenced by its structural phase transitions.

Purpose of the Study:

• To investigate the crystal structure evolution of ErVO4 under variable pressure.
• To precisely determine the phase transition pressure and equation of state.
• To investigate mechanical properties and compare experimental findings with theoretical predictions.

Main Methods:

• High-pressure single-crystal X-ray diffraction using helium as a pressure medium.
• Structure refinements up to 24.1 GPa.
• Density-functional theory calculations for mechanical properties.

Main Results:

• Observed a phase transition from zircon to scheelite structure at 7.9(1) GPa.
• No evidence of phase coexistence was detected, contrary to some previous reports.
• Determined precise linear compressibility and pressure-volume equation of state for both phases.
• Calculated mechanical properties using density-functional theory.

Conclusions:

• The zircon-to-scheelite transition in ErVO4 occurs at 7.9 GPa without phase coexistence.
• Experimental results provide accurate data on compressibility and equation of state.
• Discrepancies with theoretical predictions regarding secondary phase transitions were noted.