Microstructure, Gyromagnetic Properties, and Circulator Simulation of <i>c</i> ‐Axis Textured W‐Type Hexaferrite

ABSTRACT C‐ axis texture of W‐type hexaferrite (Ba 0.9 Gd 0.1 Zn 2 Fe 15.9 Mg 0.1 O 27 , BaW) was obtained for the first time through a ceramic process combined with magnetic field orientation. The scanning electron microscopy figure shows that most grains are hexagonal plate‐like in shape, arranged uniformly, and preferentially grow along the c ‐axis. Consequently, BaW simultaneously achieved a saturation magnetization of 72 emu/g and a remanence ratio up to 0.79. Moreover, a U‐band ferromagnetic resonance was successfully detected using a coplanar waveguide based on the perturbation method. The corresponding ferromagnetic resonance linewidth ∆H is close to 2000 Oe. The self‐biased circulator with a novel slotted structure, designed based on the gyromagnetic properties of BaW, demonstrated a good circular transmission performance in the K‐band, which highlights BaW as a potential candidate for circulator application.