GeMn-substituted barium hexaferrite

Abstract

The microwave properties have been studied on polycrystalline hexaferrite BaZn/sub 2/(GeMn)/sub 0.2/Fe/sub 15.6/O/sub 27/. The X-ray diffraction has shown that the W-type hexaferrites BaZn/sub 2/(GeMn)/sub x/Fe/sub 16-2x/O/sub 27/ can not be formed at x/spl ges/0.5. The anisotropy field of hexaferrite BaZn/sub 2/(GeMn)/sub 0.2/Fe/sub 15.6/O/sub 27/ measured at room temperature is 7.90/spl times/10/sup 5/ A/m. The exchange interaction constants and the contributions to magnetocrystalline anisotropy for various sublattices in BaZn/sub 2/(GeMn)/sub 0.2/Fe/sub 15.6/O/sub 27/ have been calculated based on the molecular field theory and H.B. Callen's single ion anisotropy model. The results show that the sublattices 12 k and 2 d have stronger contribution to anisotropy.