Pressure effects on the Raman spectrum of $CaZnF_4$

TL;DR

This study investigates how pressure affects the lattice vibrations of CaZnF4 using Raman spectroscopy up to 17 GPa, revealing pressure-induced phase transitions and irreversible structural changes.

Contribution

It provides the first detailed Raman analysis of CaZnF4 under high pressure, identifying specific pressure points where phase transitions occur.

Findings

Most Raman frequencies increase with pressure

Singularities observed at 1.5 GPa, 10 GPa, and 17 GPa

Irreversible phase transformation above 17 GPa

Abstract

The pressure influence on the lattice vibration of $CaZnF_4$ has been studied by Raman diffusion up to 17 GPa. Most Raman frequencies increase with increasing pressure. Three singularities in the pressure induced frequency evolution are observed around 1.5 GPa, 10 GPa and 17 GPa. The samples pressurized to 17 GPa or higher do not revert to the ambient pressure phase after being released, the new phase showing different Raman spectra from the ordinary one. It is suggested that $CaZnF_4$ undergoes probably sudden lattice deformations at about 1.5 GPa and 10 GPa, and an irreversible phase transformation above 17 GPa.