Preparation of bismuth-substituted yttrium iron garnet powders by the citrate gel process

The synthesis temperature and the bismuth content in bismuth-substituted yttrium iron garnet (Y3−xBixFe5O12, Bi:YIG) powders prepared by sol-gel processing were investigated, where a gel reaction of nitrates of constituent metal ions and citrate was used. Crystallographic single-phase garnet powders were obtained after the dried gel was subjected to calcination above 700 °C in air. The synthesis temperature of garnets tends to decrease with increasing Bi content. The maximum Bi substitution x is about 1.7.