ゾル·ゲル法による Bi 置換 YIG の作製と磁気持性

抄録

Bi, Al substituted YIG was synthesized by sol-gel method using a solution of yittrium, iron, bismuth and aluminum nitrates dissolved in ethylene glycol. Films were fabricated by spin-coating a gel solution onto glass substrates. Film thickness was controlled by repetitive spin-coating several times. Coated films were subjected to heat treatment in air at 700°C for 4 hours to obtain YIG crystal. Magnetization of the films with Bi_xY_3-xFe₅O₁₂ lies in the film plane. The films magnetized normal to the film plane were obtained at a composition of Y_1.5Bi_1.5Fe_3.8Al_1.2O₁₂,but magnetization tends to incline toward the film plane with increasing film thickness. This may be explained in terms of stress due to substrate constraint: Stress relief becomes remarkable as thickness increases by repetitive spin-coating. This can be, to a great extent, eliminated by heat treatment after each spin coating process. Magneto-optical Faraday rotation of the films are shown in comparison with both heat treatments.