Effect of Sc substitution on the phase composition, microstructure, and properties of (Tb1−xScx)3(Al1−yScy)2Al3O12 transparent ceramics

Abstract

Terbium aluminum garnet (Tb3Al5O12; TAG) ceramics are among the most promising magneto–optical materials owing to their outstanding comprehensive performance. Many works have focused on improving the optical quality of TAG ceramics. A key point for improving optical quality is ensuring the accuracy of the stoichiometric ratio and avoiding secondary phases. In this work, 0, 2, 4, or 6 wt% Sc2O3 was added to the TAG ceramics to increase the solid solubility. The effects of Sc substitution on the crystal structure, sintering process, microstructure, optical transmittance, and magneto–optical properties of (Tb1−xScx)3(Al1−yScy)2Al3O12 (TSAG) ceramics are studied in detail. 4 wt% Sc2O3:TAG ceramics with an in-line transmittance of 82.2% at 1064 nm and 81.2% at 633 nm were successfully fabricated, and the Verdet constant was 164.4 rad·T−1·m−1 at 633 nm. Anti-site defects (ADs) and Sc replacement in TAG are further studied via first-principles calculations to determine the working mechanism of Sc. Both the experimental and calculation results show that the introduction of Sc can effectively increase the solid solubility of TAG ceramics, suppress secondary phases, and hence improve the optical transmittance.

Keywords

• terbium aluminum garnet ceramics
• magneto–optical materials
• microstructures
• anti-site defects (ads)
• first-principles calculations