High-dielectric-constant, low-loss YIG ferrites for miniaturized microwave devices through multi-ion substitution composite regulation

Increasing the dielectric constant of yttrium iron garnet (YIG) ferrites while maintaining low losses is crucial for miniaturizing microwave devices. This paper reports a high-relative-dielectric-constant, low-loss YIG ferrite synthesized by a solid-state sintering method employing multi-ion substitution composite regulation. By substituting high-polarizability Bi 3+ ions, the relative dielectric constant was increased to over 17. Analysis based on complex chemical bond theory (P-V-L) and X-ray photoelectron spectroscopy (XPS) revealed that the dielectric constant was predominantly influenced by the ionicity of the Y/Bi/Ca-O bonds. Enhancements in lattice energy and reductions in Fe 2+ content effectively reduced dielectric losses. Appropriate ion substitution enhanced the saturation magnetization and significantly reduced the FMR linewidth. The synthesized Bi 0.6 CaY 1.4 Sn 0.4 V 0.3 Fe 4.3 O 12 exhibits superior electromagnetic properties (ε r = 17.35 @ 8.0 GHz, tanδ = 4.747×10 −4 , M s = 1437.03 Gs, ΔH = 80.02 Oe), demonstrating great potential for application in miniaturized microwave devices.