Analysis of magnetic disaccommodation in La3+–Co2+-substituted strontium ferrites

M-type strontium ferrites substituted by La3+–Co2+(Sr1−xLaxFe12−xCoxO19) were prepared by ceramic process. Effects of the substituted amount of La3+ and Co2+ on structure and magnetic properties of Sr1−xLaxFe12−xCoxO19 compounds have systematically been investigated by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and magnetic disaccommodation. In the measurement range from 80 to 500 K, the magnetic disaccommodation is represented by means of isochronal curves. It is well known that magnetic disaccommodation cannot be obviously found in the M-type of pure strontium ferrites. However, three peaks were observed in Sr1−xLaxFe12−xCoxO19, and this behavior is explained in terms of the presence of Fe2+ cation and to the site occupation by the magnetic Co2+ ionic within the hexagonal structure.