Temperature-dependent Raman scattering of DyScO3 and GdScO3 single crystals

Area of Science:

• Solid State Physics
• Materials Science
• Crystallography

Background:

• Rare-earth scandates (ReScO3) are perovskite oxides with potential applications.
• Understanding their structural stability at high temperatures is crucial for material processing and device performance.
• Previous studies have explored their properties, but high-temperature phase transitions remain an area of interest.

Purpose of the Study:

• To investigate the high-temperature structural stability of Dysprosium Scandate (DyScO3) and Gadolinium Scandate (GdScO3) single crystals.
• To determine if a structural phase transition occurs up to 1200°C.
• To analyze the temperature dependence of Raman phonon modes and their relation to structural changes.

Main Methods:

• Temperature-dependent Raman spectroscopy was performed on DyScO3 and GdScO3 single crystals.
• Measurements were conducted from room temperature up to 1200°C.
• Raman spectra were analyzed to observe shifts in phonon wavenumbers and identify any anomalies.

Main Results:

• All observed Raman modes exhibited a monotonic decrease in wavenumber with increasing temperature, with no anomalies detected.
• The spectral signature at high temperatures and extrapolation suggest a reduction in orthorhombic distortion towards a cubic structure.
• The orthorhombic-to-cubic phase transition is predicted to occur at or above the melting point of these materials.

Conclusions:

• DyScO3 and GdScO3 do not undergo a structural phase transition below their melting points.
• The observed behavior indicates a gradual decrease in orthorhombic distortion with increasing temperature.
• The study provides insights into the thermal expansion and high-temperature behavior of rare-earth scandates.