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

Abstract

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.