Phase Evolution of Yttrium Iron Garnet (YIG) Made by Solid State Sintering: Particle Size Effect

Abstract

The phase evolution of yttrium iron garnet (YIG) during reaction 3Y2O3-5Fe2O3 was investigated by modifying Fe2O3 particle sizes (FPS). Five different sizes of Fe2O3, (d50) are used to prepare YIG powder. Solid state reaction (SSR) was applied at 1200 °C in order to gain insight on the effect of FPS towards the YIG formation. Rietveld refinement method was used to quantify the amount of YIG yielded (%). Larger FPS (> 50 μm) initiates only 5Fe2O3 + 3Y2O3 à 3YFeO3 + Fe2O3 + Y3Fe5O12.. However, when the fine FPS (5 μm) is used, the reaction pathway was changed into 5Fe2O3 + 3Y2O3 à 6YFeO3 + 2Fe2O3 à 2Y3Fe5O12. These behaviors is explained that the smaller FPS consumed quickly to form YIG due to the smaller particle distance between Fe2O3 and Y2O3. This shall be leading to higher reaction rates (mass-transfer kinetics).

Investigation of YIG’s Active Site Using Density Functional Theory

“…1. The electronic configuration of the developed model are based on Fe-3d 6 4s 2 , Y-4s 2 4p 6 4d 1 5s 2 and O-2s 2 4p 4 with lattice parameters a = b = c is 12.365 Å [14] and symmetry constraints α = β = γ = 90 o . The model was simulated and optimized in a YIG supercell of 2 x 2 x 1 (as per Fig.…”