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

Highlights: • It is the first time reporting the effect of specific surface area and morphology of raw material Fe₂O₃ on the phase formation and the magnetic properties of YIG ferrites. • A larger specific surface area of raw material Fe₂O₃ will result in a decrease in slurry viscosity in mixing procedure, which promotes slurry mixing homogeneity and further promotes reactivity in calcination and sintering processes. • The specific surface area and morphology of raw material Fe₂O₃ cause the increased YIG formation rate rather than YIP (YFeO₃) due to increased surface contact of particles in the Fe₂O₃-Y₂O₃ mixture. • For proper selection of Fe₂O₃ with the specific surface area (SSA) = 7.18 g/cm², the Fe₂O₃ primary particle size would produce a 100% YIG phase, and obviously improved magnetic properties, such as 4πM_S, B_r, H_C, and Squareness ratio (SQR) were realized. The microwave property line width of FMR, ΔH, was also measured to be 36.7 Gauss at 3.2 GHz. 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.