Low temperature sintering of microwave magnetic garnet materials

Addition of 2Ca–V and Bi-species into the yttrium–iron garnet (YIG) materials markedly lowers the sintering temperature necessary for densification of the materials. Sintering temperature (Ts) needed for achieving a density larger than 97% theoretical density (T.D.) decreases from 1425 °C×6 h for pure YIG to 1280 °C×6 h for 0.6 (2Ca–V)-doped YIG, (Ca1.2Y1.8)(V0.6Fe4.4)O12, CVG. The sintering temperature needed is even lower 1100 °C×6 h for Bi-doped CVG, (Bi0.75Ca1.2Y1.05)(V0.6Fe4.4)O12. The magnetic properties of these YIG-series materials vary with the sintering temperature pronouncedly, which is ascribed to the change in sintered density with sintering temperature. The addition of Bi-species does not degrade the magnetic and microwave properties of the materials. A low temperature co-firable ceramic material, possessing good microwave magnetic properties has thus been obtained.