Microstructural and magnetic properties of Pr-BiCo co-substituted M-type Sr-Ca hexaferrites

We have synthesized the Pr-BiCo substituted hexaferrites with compositions of Sr0.8-xCa0.2PrxFe12.0-x(Bi0.5Co0.5)xO19 (0.0 ≤ x ≤ 0.5) by the standard ceramic method. Results of X-ray diffraction analysis exhibits that the synthesized hexaferrites with x from 0.0 to 0.3 are in single magetoplumbite structure, and impurity phases are observed when x ≥ 0.4. The surface morphology of magnets shows that hexaferrite grains have a hexagonal platelet shape with clear grain boundaries. The remanence first increases with x from 0.0 to 0.1, and then decreases when x ≥ 0.1. The intrinsic coercivity decreases with x from 0.0 to 0.1, and then increases when x ≥ 0.1. With x from 0.0 to 0.4, the changing trend of magnetic induction coercivity is in agreement with that of Hcj, while at x ≥ 0.4, Hcb decreases. The maximum energy product initially increases with x from 0.0 to 0.2, and then decreases when x ≥ 0.2.