Annealing Effect on Ferromagnetic Resonance and Magnetic Properties of YIG Nanocrystals Prepared by Citrate Precursor Sol-Gel Method

YIG (Y3Fe5O12) nanocrystals were prepared through citrate precursor sol-gel method by controlling the precursor's solution concentration, annealing process and obtained a single domain YIG nanocrystals at low temperature of 700 degrees C. The highest magnetization of 24.2 emu/g, lower FMR linewidth of 140 Oe was observed for the YIG sample prepared at 900 degrees C. X-ray diffraction (XRD) confirms that, we obtained only a single garnet cubic phase of YIG from 700-900 degrees C, but at 1000 degrees C a small amount of oxide phase appeared. The coercivity was increase linearly with increase annealed temperature. The mean crystallite size varies from 22.4-83.7 nm in the range of annealed temp 700 to 1000 degrees C. Variation of the linewidth, resonance magnetic field with the annealing temperature was also studied as a function of annealed temperature. Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) suggested that the annealed YIG nanocrystals were in spherical shape, small agglomeration and the size found to be same as the size determined from XRD.