Effects of Annealing and Silicon Substitution on Audio-Frequency Magnetic Properties of Single-Crystal Yttrium Iron Garnet

Audio-frequency hysteresis loops and initial permeabilities obtained from single-crystal yttrium iron garnet cores are presented. The results demonstrate the effects of annealing and silicon-substitution on bulk magnetic properties. It is found that annealing of nominally pure YIG raises substantially the initial permeability and reduces markedly the field required for saturation. Addition of 0.25 wt% SiO2 to the melt from which the garnets are grown yields a material with a strongly frequency-dependent initial permeability.