A nonstoichiometric 3 mol% Fedeficient yttrium iron garnet composition (Y3Fe4. 85O12) chemically-modified with Si and Mn was investigated with regard to microstructure characteristics and microwave magnetic properties for high power applications. The two additives, Si and Mn were added to the garnet composition by a chemical method utilizing a sol-gel reaction. The samples were sintered at 1500°C for 3 hrs in O2. An increase in Si content tends to increase bulk density and to decrease grain size. An yttrium-rich second phase found in pure Y3Fe4. 85O12 was observed to disappear with a sufficient amount of the additives. The improved microstructural characteristics were believed to contribute to the enhanced microwave magnetic properties of the garnets. For example, spin wave line width, ΔHk, which is a key factor for this application, was found to increase from 3. 1 Oe to 12. 6 Oe b y adding 0. 6 wt% SiO2 and 0. 15 wt% MnO2. This can be attributed to smaller grain size and elimination of the Y-rich phase.
Bibliographical noteFunding Information:
Supported by the NYS Center for the Advanced Ceramic Technology (CACT) at Alfred University, NY, Electromagnetic Science (EMS) Technologies Inc., Norcross, GA and Army Research Office (ARO) under Grant No. DAAH04-95-1-0278.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering