Effects of SiO 2 Addition on Microstructure and Magnetic Properties of Yttrium Iron Garnet

Pore free Yttrium Iron Garnet (YIG) ceramics with high density and low magnetic loss were manufactured by conventional ceramic processing. By small additions of SiO 2 , pores captured inside grains were effectively eliminated, and the number of pores in grain boundaries was markedly reduced. The density of specimens was 99.6% of the theoretical density. The FMR linewidth of a specimen was 47 Oe, which is comparable to that of other YIG specimens produced by more expensive and elaborate process such as hot pressing. However, adding more than 1 mol% SiO 2 deteriorated the sintering characteristics of the YIG specimen. The added SiO 2 may segregate at grain boundaries and inhibit the grain growth. As a result, the average grain size and sintered density were reduced in the case of SiO 2 addition more than 1 mol%.