Annealing Temperature Dependence of Magnetic and Optic Properties of Bi:YIG Films Deposited with Aerosol Deposition Method

Bismuth-substituted yttrium iron garnet (Bi:YIG, $Bi_0.5Y_2.5Fe_5O₁₂$) films were deposited with aerosol deposition method and their magnetic and optical properties were investigated as a function of annealing temperature. Since the ceramic films deposited with aerosol deposition method have not a perfect crystal structure due to non-uniform internal stress occurred by mechanical collision during their deposition, the post annealing could be a key process to release its internal stress and to improve its micro structure for optimizing the magnetic and magneto-optic properties of films. The crystallinity of Bi: YIG film was improved with increase of annealing temperature, and the saturation magnetization increased up to 87 emu/cc at $800^\circC$. The Faraday rotation increased up to $1.4deg/{\mu}m$ by annealing at $700^\circC$ around the wavelength of $0.5{\mu}m$. The optical transmittance of the Bi:YIG film was also improved in visible region.