Fabrication and characterizations of Tb3Al5O12-based magneto-optical ceramics

Transparent terbium aluminum garnet (TAG)-based ceramics were fabricated by vacuum pre-sintering and hot isostatic pressing (HIP) posttreatment from the co-precipitated TAG powders with different stoichiometric ratios. After component optimization, the transparent ceramics with TAG single-phase and attractive optical quality were obtained. The in-line transmittance of optimal Tb-(1+(x))3(Al0.996255Si0.003745)(5)O-12.0093625+3(x)/2 (x = -.004, -.002) ceramics (1.7-mm thick) pre-sintered at 1700 degrees C for 20 h with HIP posttreatment at 1700 degrees C for 3 h under 176-MPa Ar reaches 82.6% at the wavelength of 1064 nm. With increasing terbium components, the secondary phase TAP appears in ceramics, which significantly degrades the optical quality of TAG-based ceramics. The Verdet constant of the TAG-based ceramics at 632.8 nm is about -181 rad T-1 m(-1) at room temperature, which is about 33% higher than that of the TGG single crystals (-134 rad T-1 m(-1)).