Effect of La2O3 on the microstructure and optical performance of (Tb0.8Y0.2-xLax)2O3 ceramics

(Tb 0.8 Y 0.2-x La x ) 2 O 3 transparent ceramics were prepared by using co-precipitation method combined with pressure-less sintering in flowing H 2 atmosphere. Microstructure, optical transmittance, elements composition, and Verdet constant of the (Tb 0.8 Y 0.2-x La x ) 2 O 3 ceramics were studied. The amount of La 2 O 3 is crucial for the formation of expected transparent (Tb 0.8 Y 0.2 ) 2 O 3 . With increasing content of La 2 O 3 , the number of pores and the grain size of as-fabricated (Tb 0.8 Y 0.2-x La x ) 2 O 3 ceramics both decrease. When 4 at.% La 2 O 3 is doped, the (Tb 0.8 Y 0.16 ) 2 O 3 transparent ceramics shows the highest transmittance of 73.3% at 1400 nm wavelength. With holding time increasing from 8 h to 15 h, the average grain size of (Tb 0.8 Y 0.16 La 0.04 ) 2 O 3 ceramics gradually increases from 5 μm to 13 μm. The Verdet constant measured at 633 nm is −352 rad/T·m, which is 2.63 times higher than that of TGG. In addition, large-size ceramics with Φ 20 mm × 3 mm and Φ 30 mm × 3 mm were also successfully obtained.