Study on the Effect of Sparking Plasma Sintering on the Structure and Magnetic Properties of Yig Prepared by a Combining Method

Abstract

We presented a study on the crystal structure and magnetic properties of yttrium iron garnet (YIG), Y3Fe5O12, which was synthesized by combining sol-gel method with sparking plasma sintering (SPS). The YIG nanoparticles were prepared by sol-gel method followed by 800°C annealing for 3 hours. In particular, SPS procedures with different temperatures (700℃~900℃) and durations (30min~90min) were performed to study the influence of SPS conditions on the crystal structure and magnetic properties of YIG. The X-ray diffraction pattern and Raman spectrum confirmed the presence of YIG structure at all studied conditions. All samples were pure garnet phase except for the samples with too high temperatures (900℃) and too long duration (90min). The impurities were inferred to be due to the hypoxic environment caused by the vacuum sintering condition of SPS. The magnetic properties of YIG samples were significantly affected by SPS conditions. The YIG sample became multi-domain at the temperature as low as 750℃ and grew to 89.1nm at 850℃ for 30min duration benefiting from to the special sintering effect of SPS. Large particles with loose structure were formed by the formation of sintering neck between the adjacent particles when the SPS temperature was higher than 800℃. It is confirmed that the sample with extended duration at a moderate temperature (800℃/60min) shows the best soft-magnetic properties, whose Ms, Mr and Hc are 27.5 emu/g, 2.4 emu/g and 19.2 Oe respectively.

Keywords: Y3Fe5O12, sparking plasma sintering, rapid sintering, magnetic property, sol-gel method