SYNTHESIS OF POLYCRYSTALLINE YTTRIUM-IRON-GARNET AND YTTRIUM-ALUMINUM-GARNET FROM ORGANIC PRECURSORS

Polycrystalline Y3Fe5O12 (YIG) and Y3Al5O12 (YAG) garnets have been prepared by the organic solution technique using a novel organic precursor. The thermal decomposition of the precursor and subsequent formation of the garnet phases was studied by thermal analysis, X-ray diffraction and Fourier transform infra red spectroscopy (FTIR) including diffuse reflectance FTIR (DRIFT). The precursor of YIG decomposes to give the garnet phase as the main component at 800-degrees-C. YFeO3 and Fe2O3 are also present, and react to give YIG at higher temperatures. Single-phase YAG can be obtained from its precursor at 1100-degrees-C. The reaction proceeds via a hexagonal YAIO3 intermediate which is formed at 850-degrees-C.