Effect of specific surface area of raw material Fe₂O₃ on magnetic properties of YIG

The effect of specific surface area (SSA) of Fe₂O₃ was investigated while evaluating the raw material of Y₃Fe₅O₁₂ (yttrium iron garnet (YIG)) preparation. For YIG ferrite, the specific surface area of Fe₂O₃, rather than average particle size (D₅₀), was found to markedly affect the mixing homogeneity of powders in the mixing procedure and the magnetic properties. Increasing the specific surface area of Fe₂O₃ resulted in the increase of the remanence (B_r) and squareness ratio (SQR); meanwhile, it also caused an obvious reduction in coercivity (H_C) for the sintered specimens. An upgrade in the specific surface area of raw material Fe₂O₃ could further resulted in a decrease in slurry viscosity in the mixing procedure, which promotes slurry mixing homogeneity and further promotes reactivity in the calcination and sintering processes. Consequently, a larger B_r and SQR and a smaller H_C were obtained. In addition, good ferromagnetic resonance (FMR) line width (i.e., ΔH) properties were also realized as 36.7 Oe at 3.2 GHz using the selected Fe₂O₃. As found in this study, the strict control of raw material Fe₂O₃ is critical in tailoring suitable B_r and H_C for the YIG ferrite manufacturing process.