Effect of Tb4O7 excess on the microstructure and magneto-optical properties of TAG transparent ceramic

Abstract TAG transparent ceramics with different Tb4O7 additive contents were successfully fabricated using solid state reaction and vacuum sintering. The samples (T1-T5) added with 0-0.3 wt% Tb4O7 exhibit high transparency in the visible and near infrared regions. It was found that adding 0.1–0.2 wt% Tb4O7 was in favor of eliminating pores and optimizing magneto-optical properties and the ceramic added with 0.1 wt% Tb4O7 (T2) possesses the highest transmittance, which reached 80.32% at 1064 nm. The TAP phase was detected by XRD and appeared in the microstructure of sample T7 with added 0.8 wt% Tb4O7 content, which inhibited grain boundary migration and deteriorated the optical quality of TAG transparent ceramics. The Verdet constant increases slightly with a small increase in the amount of Tb4O7 addition and the value of sample T5 added with 0.3 wt% Tb4O7 is 177.5rad/(T·m), which is 32% higher than that of the commercially TGG crystal.