Microstructure and Magnetic Property of M-Type SrRExFe12-xO19 by Sol-Gel Method

Magnetoplumbite-type (M-type) SrRExFe12-xO19 (RE = La and Ce, x = 0 similar to 1.0) powders were prepared by a citric acid sol gel technique and subsequent heat treatment. The crystal structure, grain size and magnetic properties were investigated by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and vibrating sample magnetometer (VSM). The XRD patterns show that SrRExFe12-xO19 (RE = La and Ce) are mainly hexagonal magnetic plumbite structure, and the average grain size of 30 similar to 40 nm was calculated using the Scherer's equation based on the XRD spectrum. Substitution of Fe ion by the rare earth La ion causes a significant decrease in intrinsic coercivity (Hc) and a slight decrease in saturation magnetization (Ms) as shown in the magnetization hysteresis loops. However, the Hc rises gradually in a small wave pattern with the increase of doping content of the rare earth Ce. The relation between the crystal structure and magnetic properties was also studied in this work.