Effect of (Ni, Zn)Ru mixtures on magnetic properties of barium hexaferrites yielded by high-energy milling

The room temperature magnetic properties and the cation site preferences of NiRu and ZnRu substituted barium hexaferrite BaFe12−x(Ni,Zn)xO19 (0⩽x⩽0.3) were investigated by vibrating sample magnetometry and Mössbauer spectroscopy. (Ni,Zn)Ru substitutions led to a great increase in the saturation magnetization (66.5 Am2/kg) at low concentrations. Mössbauer spectroscopic studies showed that both mixture ions mainly occupy the 4f2 and 2a+4f1 sites. NiRu and ZnRu mixtures showed differences in Ms presumably due to the magnetic nature of divalent ion. Hci could be easily controlled from 381.1 to 37.4 kA/m with Ms enhancement for both substitutions, mainly due to selective occupation of nonmagnetic cations on sublattice sites. The tetravalent Ru4+ ion seems to enhance Ms and to decrease Hci markedly at low substitutions.