| 摘要 |
PROBLEM TO BE SOLVED: To provide the subject garnet thick film material that is used as a substitute material for a Tb-Bi based garnet thick film material having essential absorption in an about >=1.6 μm wavelength band region and has improved insertion loss (improved transmissivity) and an improved θf/ T (temp. coefficient of Faraday rotation angle (θf ) value in a >=1.5 μm wavelength band region in which an unfavorable influence on the absorption spectrum due to Th ions is caused, and also to provide the production of this material. SOLUTION: This film material is a bismuth-substituted garnet thick film material which is produced by an LPE(liquid phase epitaxy) method with NGG (neodymium gallium garnet, Nd3 Ga5 O12 ) as the substrate and has a composition represented by the chemical formula Gd3-x-y-2 Yx Yby Biz Fe5-a Ala O12 (wherein: each of (x) and (y) is a numerical value of 0 to 0.2 and when any one of (x) and (y) is 0, the other is not 0; (z) is a numerical value of 0.8 to 1.4; and (a) is a numerical value of 0.2 to 0.7) and also contains 0 to 3.7 wt.% B2 O3 . The material is subjected to heat treatment while maintaining the material at 950 to 1,130 deg.C in an atmosphere having a >=5% oxygen concn. |
