Effects of Bi2O3 on FMR linewidth and microwave dielectric properties of LiZnMn ferrite

Effects of Bi2O3 on ferromagnetic resonance (FMR) linewidth and microwave dielectric properties for LiZnMn ferrite prepared by a conventional ceramic method were investigated. The FMR linewidth had been separated to anisotropy and porosity line broadening contributions by an approximate calculation based on spin-wave approach. The results manifest that, Bi2O3 content significantly affects FMR linewidth via promoting grain growth and densification. With Bi2O3 concentration increasing, anisotropy contribution is changeless with a constant about 80 Oe. The variation of the porosity line broadening contribution, however, is unanimous with the FMR linewidth. Meanwhile, the mechanism of dielectric polarization and dielectric loss of the samples were discussed. When the amount of Bi2O3 is 1.00 wt%, the sample shows low FMR linewidth (ΔH, 133 Oe) and low dielectric loss tangent (tan δε, 5 × 10−4) at 9.2 GHz, high saturation magnetization (Ms, 415 kA/m), and high squareness ratio (Br/Bs, 0.87).