Structural and magnetic properties of yttrium aluminum iron garnet (YAlG) nanoferrite prepared via auto-combustion sol-gel synthesis

This research investigated the structural, microstructural, and magnetic properties of yttrium aluminum iron garnet (Y3AlxFe5-xO12, YAIG) (x = 0.4, 0.8, 1.2, 1.6, 2.0, 2.4, and 2.8). The samples were prepared via auto-combustion sol-gel technique, using citric acid as chelating agent and fuel for the combustion process. The obtained powder was heated at 950 degrees C, and part of it was pressed into pellet and sintered at 1200 degrees C. The garnet phase formation was studied by X-ray diffraction, using the powder samples. Lattice constant of the samples was found to decrease from 12.4672 to 12.2540 as Al increase from x = 0.4 to 2.8. The garnet structure was confirmed by FTIR, where the main vibrating modes were observed to shift to higher wave number with increasing Al concentration. Saturation magnetization, M-s., shows a decreasing trend from 10.0450 to 0.1887 emu/g with increasing Al from 0.4 to 2.8. The decreasing trend in the static magnetic properties of YAIG samples is attributed to the introduction of Al ions in the YIG crystal lattice. High Al content of the samples changed their property from ferrimagnetic to paramagnetic at x > 1.6. The grain size decreased from 0.46 to 0.27 mu m, as Al increased from x = 0.4 to 2.8.