(95y) Flame Synthesis of Yttrium Iron Garnet

Yttrium Iron Garnet (YIG) is a ferromagnetic material with the composition Y3Fe5O12. Its rhombohedral crystal lattice contains two different atom sites that interact anti-ferromagnetically causing the net magnetic moment of the entire crystal structure to be equal to that of one Fe atom. This gives YIG excellent magnetic and magneto-optic properties such as large Faraday rotation, high quality factor in the microwave region, smallest linewidth in magnetic resonance and good transmittance in the infrared region. These properties make YIG one of the most effective soft magnetic materials used extensively in microwave devices including isolators, circulators, and dephasers. They are also used in solid-state lasers, media storage and optical applications.

Some properties of YIG such as its coercivity and magnetic anisotropy can be affected by the method of preparation. In this work the synthesis and characterization of YIG particles with Y:Fe ratios of 3:5, 4:5 and 3:6 using a single step flame spray pyrolysis method is reported. The process involves the pyrolysis of aqueous precursor solutions of the metal nitrates without addition of any extra fuel in the methane oxygen flame. The primary particle size of samples prepared with a 3:5 mole ratio of Y:Fe was found to be in the range of 25-30 nm from TEM imaging and the material is crystalline, containing a mixture of YIG, Fe¬2O3 and YFeO3 according to X-ray diffraction measurements. BET analysis showed the surface area of the particles formed to be 48m2/g. The saturation magnetization of the prepared samples was also shown to increase with an increase yttrium oxide concentration. The curie temperatures of samples synthesized were also measured and reported.