Crystal structure and magnetic properties of Gd-Cu substituted M-type Sr-hexaferrites synthesized by the co-precipitation method

The hexagonal strontium ferrites doped with diverse molar ratio of gadolinium and copper (Sr1-xGdxFe12-xCuxO19, x = 0.00, 0.05, 0.10, 0.15 and 0.20) were prepared by the co-precipitation method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) were employed to analyze the phase structure, morphology and magnetic performance, respectively. The samples with x from 0.00 to 0.10 were confirmed to a single magnetoplumbite phase, and the impurity phases were detected when the content of dopants x >= 0.15. The surface morphology of Sr1-xGdxFe12-xCuxO19 presented hexagonal shape and revealed average grain size increased with the increasing Gd-Cu substitution amount. With the increase of doping amount x, the saturation magnetization (Ms), remanent magnetism (Mr) and coercivity (Hc) firstly increase, and then decrease. When x was 0.10, the Hc arrived at 7203.42 Oe.