Preparation and magnetic properties of low temperature sintering Bi-substituted yttrium iron garnet

The low temperature sinterability and magnetic properties of Bi-substituted yttrium iron garnet (YIG) polycrystalline samples were studied in this paper. The results showed that Bi-substitution can lower garnet phase formation temperature from about 1200degreesC to 900degreesC and ceramic sintering temperature from over 1300degreesC to about 1050degreesC respectively. The Bi-substitution leads to a decrease in initial permeability and an increase in ferromagnetic resonance linewidth (AH) of sintered specimens. Saturation magnetization decreases and coercive force increases a few with an increase of Bi content. The mechanism of Bi-substitution on initial permeability and All. is discussed. The change in initial permeability of Bi-substituted specimens relative to unsubstituted YIG results from Bismuth volatilization and weakening of superexchange interaction. The lattice dilatation in Bi-substituted YIG gives cause for a decrease of saturation magnetization and art increase of coactivity force.