Magnetic and Microwave Absorbing Properties of M-type Hexagonal Ferrites Substituted by Ru-Co (BaFe12-2xRuxCoxO19)

In this study, the magnetic (static and high-frequency) and microwave absorbing properties have been investigated in Ru-Co substituted M-hexaferrites (BaFe12-2xRuxCoxO19). The powders and sintered specimens were prepared by conventional ceramic processing technique. With the calcined powders, the composite specimens were prepared using the silicone rubber as a matrix material. The substitution ratio of Ru-Co to obtain in-plane magnetic anisotropy, thus having the minimum coercivity, is much smaller (about x = 0.3) than the previously reported Ti-Co substituted specimen. Owing to this low substitution, the specimen has a large value of saturation magnetization (M-s = 65 emu/g). Ferromagnetic resonance behavior and microwave absorbing frequency band is strongly influnced by the coercvity which can be controlled by Ru-Co substitution ratio. It is found that the M-hexaferrites with planar magnetic anisotropy by doping Ru-Co in both sintered and composite form have superior microwave absorbing properties in GHz frequency range.