Synthesis and characterization of Sr_1−x Y _x Fe₁₂O₁₉ hexaferrites prepared by solid-state reaction method

M-type permanent magnetic ferrite Sr_1−x Y _x Fe₁₂O₁₉ (x = 0.00, 0.02, 0.05, 0.08, 0.10, 0.13) magnetic powders have been synthesised by the ceramic process. Phase composition was examined by using X-ray diffraction (XRD). The single magnetoplumite phase structure transformed into multiphase structure with the increase of yttrium content, where the small amount of hematite phase existed in M-type phase. It was found that powders were crystallized into M-type hexaferrites phase at 1250 °C. The micrographs of the magnetic powders were observed by a field emission scanning electron microscopy (SEM). The micro-morphology of the particles exhibits the uniform plane hexagonal structures of M-type ferrites with different yttrium contents. Vibrating sample magnetometer (VSM) was employed to investigate the magnetic properties. With the increasing of yttrium content, the saturation magnetization (Ms) first increases and then decreases. The saturation magnetization (Ms) has the maximum value at x = 0.05 (Ms = 62.74 emu/g). The value of coercivity (Hc) increases with the increasing of yttrium content, and the value of coercivity (Hc) is up to 3634 Oe when the amount of doping is 0.13.