| abstract |
In ceramics containing, as a main component, at least 40% of terbium oxide (formula: Tb 2 O 3 ) in a molar ratio and at least one oxide selected from yttrium oxide, scandium oxide, and lanthanide rare earth oxide, (1) the terbium oxide The crystal structure of the ceramics of the system does not contain abnormalities other than cubic crystals, (2) the average crystal grain diameter is in the range of 0.5 to 100 µm, and (3) abnormalities other than cubic crystals in the crystal structure of the terbium oxide ceramics. Transparent ceramics containing a sintering aid that does not precipitate. The transparent ceramics according to the present invention can provide a magneto-optical device having a performance equivalent to or higher than that of a conventional single crystal material such as terbium gallium garnet or the like. Even in optical loss and optical uniformity, there are very few birefringent components, very little scattering, and a functional element in the optical isolator in the infrared region of 500 nm or more and 1.5 µm or less can be provided. |