Temperature-dependent Raman scattering of DyScO3 and GdScO3 single crystals

TL;DR

This study investigates how Raman phonon modes in DyScO3 and GdScO3 single crystals shift with temperature up to 1200°C, revealing no phase transition and suggesting a transition near or above melting point.

Contribution

It provides detailed temperature-dependent Raman data for DyScO3 and GdScO3, indicating the absence of structural phase transitions below melting point and insights into lattice distortion behavior.

Findings

All Raman modes decrease monotonously with temperature

No structural phase transition observed up to 1200°C

Orthorhombic distortion decreases towards cubic structure

Abstract

We report a temperature-dependent Raman scattering investigation of DyScO3 and GdScO3 single crystals from room temperature up to 1200 {\deg}C. With increasing temperature, all modes decrease monotonously in wavenumber without anomaly, which attests the absence of a structural phase transition. The high temperature spectral signature and extrapolation of band positions to higher temperatures suggest a decreasing orthorhombic distortion towards the ideal cubic structure. Our study indicates that this orthorhombic-to-cubic phase transition is close to or higher than the melting point of both rare-earth scandates (\approx 2100 {\deg}C), which might exclude the possibility of the experimental observation of such a phase transition before melting. The temperature-dependent shift of Raman phonons is also discussed in the context of thermal expansion.