C-axis oriented polycrystalline BaNi2GdxFe16-xO27 (x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) for the application of self-biased circulator at K band

Abstract

The grains of oriented W-type hexaferrite BaNi2GdxFe16-xO27 (BaW) where x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 grew uniformly along their c-axis perpendicular to the sample plane, which meant high remanence ratio of BaW. When Gd3+ substitution content was x = 0.0, the corresponding remanence ratio reached as high as 0.90. When x = 0.2, the oriented BaW simultaneously possessed high saturation magnetization (Ms= 58.36 emu/g), high coercivity (Hc = 1527 Oe), high remanence ratio (Mr/Ms = 0.85), relatively low magnetocrystalline anisotropy field (Ha = 10,253 Oe) and low ferromagnetic resonance linewidth (ΔH = 624 Oe). These characteristics indicated the material was suitable for the design of self-biased circulator operated at K band. Based on the BaW material, self-biased double Y-junction microstrip circulator was designed and realized well circulatory function at K band.