Coercivity, Activation Volumes, and Interactions in BaFe₁₂O₁₉

Abstract

Coercivity and magnetic viscosity studies are presented in coprecipitated and ceramic BaFe12O19 hexaferrites. According to magnetic viscosity formalism, the activation volumes are obtained and for ceramic sample the temperature dependence of the activation volume is reported. Using remanence curves, interactions are evaluated by means of the ΔM technique. In both samples, interactions are evidenced, particularly demagnetizing‐like interactions. The activation volume values seem to indicate that coherent rotation is not the mechanism of magnetization reversal even in the sample with particle size below the critical single‐domain size. It is confirmed that the activation volume increases with temperature in 75–300 K temperature range, for both coprecipitated and ceramic samples.