Influence of cobalt substitution on the magnetocrystalline anisotropy of X-type hexaferrites Sr2CoxFe30−xO46

Abstract We investigate the composition dependence of the magnetic properties in X-type hexaferrites Sr2CoxFe30−xO46. We prepared single crystals including various contents of cobalt ions using a flux method. The samples with x ≥ 1.58 exhibited a different behavior in the 2 1 - 1 - 0 and 01 1 - 0 directions at 100 K, which was observed by magnetic measurements and Lorentz transmission electron microscopy. Such anisotropy was not observed in the sample that included slightly less cobalt ions (x = 1.32). In contrast, the Curie temperature was independent of the cobalt content. It was concluded that such strong magnetocrystalline anisotropy was caused by the cobalt ions especially at low temperature.