Some interesting properties of polycrystalline garnets containing Co2+ions

Four series of polycrystalline Y, Gd, I, and garnets, containing Co²⁺and counterbalanced by Si⁴⁺have been studied. The permeability shows a pronounced peak (up to μ = 500); the coercive force and the gyromagnetic linewidth show minimums for small substitutions of cobalt. These experimental features are in connection with the possibility of having a compensation of the magnetocrystalline anisotropy of Fe³⁺ions by Co²⁺octahedral ions. After a comparison between cobalt-doped garnets and classical Y, Gd, Al garnets, it is possible to conclude that the cobalt doping is a new interesting way to improve the microwave materials.