Synthesis of polycrystalline yttrium iron garnet and yttrium aluminium 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 °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 °C. The reaction proceeds via a hexagonal YAlO₃ intermediate which is formed at 850 °C.