An insight into formation mechanism of rapid chemical Co-precipitation for synthesizing yttrium iron garnet nano powders

Abstract

The rapid chemical co-precipitation method is supposed to be a stable way to synthesize high quality cubic yttrium iron garnet (YIG) nanopowders. In this paper, focusing on clarifying its formation mechanism, the thermal behaviors and the elemental distributions of the chemical co-precipitated precursors have been analyzed by simultaneous differential scanning calorimetry plus thermal gravimetric analysis (DSC-TGA) and energy disperse spectroscopy (EDS) mapping technique on a transmission electronic microscope. The results indicated that the homogeneity of Y and Fe elemental distributions in the precursor powders determines the process through which the cubic YIG phase would form: one experiences the intermediate tetragonal YIG phase; the other takes YFeO3 as the intermediate phase. The homogenous distributions of Y and Fe elements in the precursor powders at the scale below 50 nm forms the intermediate tetragonal YIG phase rather than YFeO3, which leads to reduction of the formation temperature for synthesizing the single phase YIG. The obtained YIG nanopowders with the average particle size below 100 nm show excellent magnetic properties with saturation magnetization of 26 emu/g and coercive field of 45 Oe. This clear formation mechanism of YIG nanopowders is suitable for optimizing the processing conditions for the chemical precipitation synthesis of YIG nanopowders at large scale.