Preparation of nanocrystalline bismuth-substituted yttrium iron garnet films with enhanced Faraday magneto-optical figure of merit by pyrolysis of coprecipitated hydroxide slurry

Nanocrystalline Bi-substituted yttrium iron garnet films have been prepared by coprecipitation titration, once-through coating of hydroxide slurry, and pyrolysis. The resulting films with grain sizes of 10-20 nm are fabricated at a pH value of 12 and heat treated of 700 °C for 1 h. At the incident light wavelength of 633 nm, the maximum special Faraday rotation of 3.6×104°/cm and Faraday magneto-optical figure of merit of 6.7°/dB were obtained. The influence of pH value and heat treatment on film grain size, crystallinity, and magneto-optical properties is demonstrated.