Combining Soft Chemistry and Spark Plasma Sintering to Produce Highly Dense and Finely Grained Soft Ferrimagnetic Y3Fe5O12 (YIG) Ceramics

We report the synthesis of yttrium iron garnet (YIG) combining soft chemistry route, namely the polyol process, and spark plasma sintering (SPS) technique. The polyol process produced an intermediary amorphous phase containing both iron and yttrium cations in the desired ratio. They were annealed at 400 degrees C in air to decompose the organic content of the reaction (polyol and acetate). To achieve the garnet phase, the polyol-obtained precursor was subjected to reactive SPS treatment at a temperature of 750 degrees C, far below the typical temperatures (1350 degrees C) used in the classic solid-state reaction process. In 15min pure and high-density Y3Fe5O12 ceramic, with about 100nm sized crystalline grains, was obtained. We report as well the characterization of the initial amorphous phase and the obtained YIG by X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, Fe-57 Mossbauer spectrometry, and magnetization measurements.