The Structural and the Magnetic Properties of Aluminum Substituted Yttrium Iron Garnet

In this paper, Y3AlxFe5-xO12 powders with x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 were prepared via solid state reaction method. X-ray diffraction, Vibrating Sample Magnetometry, and Mossbauer Spectroscopy were used to study their structural and magnetic properties. The XRD patterns of the samples show single phase structure with decreasing lattice constant when increasing Al concentration. The saturation magnetization decreases from 28.0 to 10.1 emu/g with increasing Al3+ from 0.0 to 1.0 due to the reduction of the superexchange interactions between iron ions in the a and d sublattices. Room temperature Mossbauer spectra for the samples were collected and analyzed. The hyperfine field values for octahedral and tetrahedral sites of the samples decreased with increasing Al concentration. Moreover, Mossbauer results have shown that Al3+ ions prefer to replace Fe+3 at the octahedral sites.