| abstract |
A transparent complex oxide sintered body is manufactured by sintering a compact in an inert atmosphere or vacuum, and HIP treating the sintered compact, provided that the compact is molded from a source powder based on a rare earth oxide: (TbxY1-x)2O3 wherein 0.4≤x≤0.6, and the compact, when heated in air from room temperature at a heating rate of 15° C./min, exhibits a weight gain of at least y % due to oxidative reaction, y being determined by the formula: y=2x+0.3. The sintered body has a long luminescent lifetime as a result of controlling the valence of Tb ion. |