MAGNETIC-ANISOTROPY OF CHEMICALLY COPRECIPITATED ZN2W FERRITE

BaZn2Fe16O27 is prepared by several modified coprecipitation methods a nd studied using differential thermal analysis, X-Ray analysis, static magnetic measurements and ferromagnetic resonance absorption. At low annealing temperatures M- and W-type ferrite as well as monoferrite Zn Fe2O4 crystallize depending on the coprecipitation method In powders a nnealed below 1100-degrees-C single-domain hexaferrite phase with unia xial anisotropy comparable to Zn2W ferrite mainly effects the microwav e absorption loss. Ferromagnetic resonance is used to determine an eff ective anisotropy field strength of H'A = 2K'1/mu0M(S) equal to 979 kA /m and K2/K'1 = - 0.03 leading to K2 = - 7.9 kJ/m3 for these powders.