GROWTH-INDUCED MAGNETC ANISOTROPY IN (BiAI)YIG THIN FILMS
（BiAl）YIG薄膜的生长感生磁各向异性

ince Bi-substituted YIG thin films,such as (BiAI)YIG thin film, have large Faraday rotation, they are widely used for magneto -optic waveguide applications. As an importmant magnehc anisotropy, the growth-induced magnetic anisotropy in (BiAI)YIG films have been theoretically and experimentally investigated to be connected with Fe3+ and Fe2+ ions. Since Bi3+ has a large spin-orbit coupling bismuth substitution seems to be an indirect influence of Bi(3+)ion on nearest Fe(3+) ions via intervening O(2-) ions which leads to a modification of the second order crystal fields parameters of the Fe(3+) near to a Bi(3+),its magnitude is determined by the content and preferential distribution of Bi(3+) ions in dodecahedral siter. Fe(2+) ions caused by high valence ions and oxygen vacancy also give contributionsto the growth-induced magnetic anisotropy, its magnitude is determined by the content and preferential distribution of Fe(2+) ions in octahedral sites. Al(3+) ions in (BiAl)YIG film act as a dilution to decrease the concentration of Fe(3+) ions, which decrease the growth-induced magnetic anisotropy constant. So for waveguide, the magnetization should lie essentially parallel to the film plane, which can be achieved by annealing at a high temperature to randomize the bismuth and yttrium ions arrangement and avoiding the incorPOration of high valence ions and oxygen vacancy.