Magnetocrystalline Anisotropy and FMR Linewidth of Zr and Zn-Doped Ba-Hexaferrite Films Grown on MgO (111)

Ba M-type ferrite films of composition BaFe₁₁Zn_0.5Zr_0.5O₁₉ were grown on MgO (111) substrates by pulsed laser deposition. Both Zn and Zr divalent ions were introduced to reduce the magnetic anisotropy field to ~7.5 kOe, or 46% lower than the parent Ba M-type compound. Temperature dependence of magnetization over 25 to 350°C was investigated, indicating a Curie temperature of 320°C. Ferromagnetic resonance linewidth, as the peak-to-peak power absorption derivative at 9.55 GHz, was 120 Oe. The substituted sample had a K₁ of ~0.920 × 10⁶ erg/cm³. Such sample properties provide an attractive option for self-biased microwave devices applications operating at X (8-12 GHz) and Ku bands (12-18 GHz) as circulators and isolators.