Synthesis, crystal structure and magnetic characterization of Pr3+ and Zn2+ ions co-doped hexagonal ferrites via the ceramic process

M-type hexaferrites Ca0.2Sr0.8-xPrxFe12-yZnyO19 (0.00 ≤ x ≤ 0.40, 0.00 ≤ y ≤ 0.30) were synthesized by the ceramic process. The X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and a vibrating sample magnetometer (VSM) were used to investigate microstructure and magnetic properties of the M-type hexaferrites. The single-phase with hexagonal structure was obtained in all Pr-Zn substituted M-type hexaferrites, and with increasing Pr-Zn content, the 2θ values of (107) and (114) peaks shifted towards higher angles. With increasing Pr-Zn content, the lattice constant a basically kept unchanged, while the lattice constant c decreased. FESEM images of the hexaferrites showed that the hexagonal platelets had formed in the hexaferrites and the average grain size increased with increasing Pr-Zn content. The saturation magnetization (Ms), remanent magnetization (Mr) and Mr/Ms ratio first increased with increasing Pr-Zn content (0.00 ≤ x ≤ 0.24, 0.00 ≤ y ≤ 0.18), and then decreased with further increasing Pr-Zn content. The coercivity (Hc), magnetic anisotropy field (Ha) and effective magnetic anisotropy constant (Keff) increased with increasing Pr-Zn content (0.00 ≤ x ≤ 0.16, 0.00 ≤ y ≤ 0.12), and then decreased with further increasing Pr-Zn content.