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

(Tb0.8Y0.2-La-x(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 (Tb0.8Y0.2-La-x(x))(2)O-3 ceramics were studied. The amount of La2O3 is crucial for the formation of expected transparent (Tb0.8Y0.2)(2)O-3. With increasing content of La2O3, the number of pores and the grain size of as-fabricated (Tb0.8Y0.2-La-x(x))(2)O-3 ceramics both decrease. When 4 at.% La2O3 is doped, the (Tb0.8Y0.16)(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 (Tb0.8Y0.16La0.04) O-2(3) ceramics gradually increases from 5 mu m to 13 mu m. The Verdet constant measured at 633 nm is 352 rad/T center dot m, which is 2.63 times higher than that of TGG. In addition, large-size ceramics with phi 20 mm x 3 mm and phi 30 mm x 3 mm were also successfully obtained.