The magnetic properties of permanent strontium ferrite doped with rare-earth by chemical co-precipitation method

Abstract

The Sr1-xSmxFe12-xCuxO19 (0 ≤ x ≤ 0.2) materials were prepared by chemical co-precipitation technique. The products were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electric microscopy (SEM) and vibrating sample magnetometer (VSM). The results of XRD showed that the pure M-type hexaferrites are obtained. The Sm3+ and Cu2+ ions were completely doped into strontium ferrite phase. With the increasing of Sm-Cu content, the grain size gradually increases. The FTIR spectra of annealed samples of Sr1-xSmxFe12-xCuxO19 showed that strontium hexaferrite particles have been successfully synthesized and M-type SrFe12O19 intrinsic crystal structure has not been destroyed. A filed emission scanning electric microscopy was employed to explore the micrographs of the magnets. The hexaferrite magnets have formed hexagonal-shaped crystals. The magnetic properties were tested by VSM. In the single M-type phase region, the variation of magnetic properties with Sm-Cu substitution amount is well explained based on the occupancy effect of Sm3+, Cu2+ in magnetoplumbite structure. The results indicate that the Br increases and then decrease when rare-earth content (x) continutes to increase. With the dosages of Sm-Cu from 0 to 0.20, the Hc at x = 0.15 reach the maximum value of 6862.62 Oe.