The magnetic properties of permanent Strontium Ferrite doped with rare-earth by Chemical co-precipitation method

【摘要】：The Sr_(1-x)Sm_xFe_(12-x)CU_xO_(19)(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 XRD results showed that the pure M-type phase is obtained for the Sr_(1-x)Sm_xFe_(12-x)CU_xO_(19)(0≤x≤0.2).The Sm~(3+)and Cu~(2+) 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 Sr_(1-x)Sm_xFe_(12-x)CU_xO_(19) showed that strontium hexaferrite particles have been synthesized successfully and did not change M-type Sr_1Fe_(12)O_(19) intrinsic crystal structure.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 Sm~(3+),Cu~(2+) in magnetoplumbite structure.The results indicate that the B_r increases and then decrease when rare-earth content(x) continutes to increase.With the dosages of Sm-Cu from 0 to 0.2,the B_r at x=0.1 reach the maximum values of.40emu/g.