| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a crystal of terbium oxide for magneto-optical elements which is excellent in transmittance and contains a trivalent Tb ion at a high concentration. <P>SOLUTION: The light-permeable crystal of terbium oxide for magneto-optical elements is represented by the composition formula (Tb<SB POS="POST">1-a</SB>M<SB POS="POST">a</SB>)<SB POS="POST">2</SB>O<SB POS="POST">3</SB>(wherein M represents one or more elements selected from Er, Tm, Yb, Lu and Sc, and 0.01≤a<0.3), the crystal concerned being a crystal of the cubic system and its linear transmittances being 70% or larger per 3 mm length both at 1.06 μm and at 532 nm. A method for producing the crystal is preferably a skull melt method, and a floating zone method can also be employed. In the skull-melt method, a raw material 2 for crystal growth is charged into a water-cooled container 1, and the center part of the raw material is heated to a high temperature for melting, but the envelope 2a of the outside part of the raw material 2, which contacts the water-cooled container, is not melted but sintered and densified to be a skull-like one, and is then made to work as a crucible. Then, after the raw material 2 is sufficiently melted, high-frequency power is decreased, and the container 1 is lowered to cool it from the bottom to crystalize the raw material concerned. <P>COPYRIGHT: (C)2013,JPO&INPIT |
