Tailoring magnetic properties of Al-substituted M-type strontium hexaferrites

Ferrites which have relatively high remanence ratio, large coercivity and strong anisotropy are needed to meet the increasing demand for devices used in millimeter-wave frequency. Herein, we demonstrate a composition of Sr 0.7 La 0.3 Fe 12− x Al x O 19 hexaferrites prepared by the conventional ceramic method. We investigate the phase, morphology and magnetic properties of Al-substituted strontium hexaferrites. This study illustrates that aluminum substitution has a significant effect to improve the coercivity and anisotropic field. Finally, we propose an empirical relationship between the functional properties of Al-substituted ferrites and the amount of aluminum.