Structural and Magnetic Studies of Aluminum Substituted YIG Nanoparticles Prepared by a Sol-Gel Route

Abstract

The aluminum substituted Yttrium Iron Garnet nanoparticles were synthesized by sol-gel route followed by annealing at 700°C and 900°C for 3 and 2 h respectively. The XRD patterns of all the samples confirmed the single-phase and well-defined garnet structure at 900°C. The average crystallite size of the samples calculated using Scherrer formula was found in the range of 56–69 nm. The lattice parameter and d-spacing were found to decrease with increasing aluminum content due to the smaller ionic size of the Al3+ cation. FTIR spectra confirmed the garnet phase formation and showed stretching mode of YIG tetrahedron in the range of 552–657 cm−1. It was observed from hysteresis loops that the saturation magnetization (Ms) values decreased from 20.69 emu/g to 3.09 emu/g with increasing aluminum content. Electron spin resonance (ESR) study showed the broadening of a peak to peak linewidth with increasing aluminum content. The minimum linewidth of 110 gauss was observed for YIG sample.