Low-fired Bi-Li-V substituted YIG ferrite for high-power microwave device application

To meet high-power microwave system demands, low-temperature sintered Bi-Li-V substituted YIG ferrites were prepared. The experimental results reveal that Bi 3+ , Li + , and V 5+ occupy the c, a, and d sites of the garnet structure, respectively; the full-site distortion reduces the lattice activation energy, significantly reducing the transformation temperature from perovskite to garnet phase. Additionally, a dual structure with a high percentage of fine grains is observed in the substituted samples, which is an important reason for the large increase in spin-wave linewidth. Isothermal thermodynamic analysis indicates that a sintering mechanism dominated by liquid-phase sintering is conducive to the densification of YIG ferrites. Ferromagnetic resonance linewidth decomposition confirms that, due to the simultaneous increase in the saturation magnetization and the magneto-crystalline anisotropy constant, anisotropy-induced linewidth remains almost unchanged; the dense dual structure leads to a significant reduction in porosity-induced linewidth; ultimately, the ferromagnetic resonance linewidth is greatly reduced.