The effects of sintering additives on sinterability and microwave properties of yttrium iron garnet

The effects of small addition of either Bi2O3 or a mixture of CuO + B2O3 on sinterability and microwave properties of yttrium iron garnet (YIG), prepared using conventional ceramic method, have been studied by means of scanning electron microscopy, X-ray diffractometry, magnetometry and ferrimagnetic resonance experiments. Sintering temperature for YIG could be reduced by amount 50 K or 150 K by adding small amount of Bi2O3 or a mixture of B2O3 + CuO, respectively. CuOFe2O3 particles formed on free surface of the samples sintered with the mixture of B2O3 + CuO. Saturation magnetization and Curie temperature of YIG samples were almost independent of the addition of sintering additives. YIG specimens sintered at 1623 K with 1.5 Wt.% Bi2O3 and YIG sintered at 1523 K with 1.0 wt.% of Bi2O3 + CuO mixture showed ferrimagnetic resonance linewidth ΔH of 62 Oe and 58 Oe, respectively, compared with 65 Oe in pure YIG specimen at 1673 K for 2 hrs. (author)