Structural and magnetic properties of Ni substituted M-type Ca-Sr hexaferrites synthesized by solid-state reactions

In this study, we have prepared the M-type Ca-Sr hexaferrites with composition of Ca0.2Sr0.8Fe12.0-xNixO19 (0.0 ≤ x ≤ 0.8) by thesolid-state reactions. The phase compositions of the samples were confirmed by X-ray diffraction analysis. The results of Xraydiffraction patterns show that for the M-type hexaferrite magnetic powders with the Ni content (x) from 0.0 to 0.4, theXRD patterns belong to the M-type strontium hexaferrite; when Ni content (x) ≥ 0.6, Sr4Fe6O13 is detected. It is observed thatlattice parameter c first increases with the increase of Ni content (x) from 0 to 0.4, and then decreases when Ni content (x) ≥0.4, while lattice parameter a basically keeps constant. Magnetization properties were measured at room temperature by apermanent magnetic measuring system. The remanence (Br) first increases with increasing Ni content (x) from 0.0 to 0.2, andthen decreases when Ni content (x) ≥ 0.2. The the intrinsic coercivity (Hcj), magnetic induction coercivity (Hcb) and maximumenergy product [(BH)max] decrease with the increase of Ni content (x) from 0.0 to 0.8.