Magnetic property and cation distributions in boron-doped MFe 2O 4( M?=?Ni, Mn) spinel ferrites

摘要

(A)[B]2O4spinel ferrites with initial compositions, BxM1?xFe2O4(M?=?Ni or Mn), were prepared using the solid state reaction technique. X-ray photoelectron spectra indicate that there were only 25% of boron ions in the end samples while the remaining boron ions were lost in the thermal treatment process. Therefore, the end samples have a composition of Bx1Mx2Fe3?x1?x2O4(M?=?Ni or Mn). X-ray diffraction patterns showed that the end samples possess a single-phase cubic spinel structure. For the two series of samples, the observed dependencies on the boron content,x1, of the sample magnetic moments at 10?K were fitted successfully by using the quantum mechanical potential barrier model. The cation distributions were obtained in the fitting process, during which the magnetic moment direction of the Mn3+cations was assumed to anti-ferromagnetically couple with those of other cations whenever they are at the (A) or [B] sites in the samples, according to the O 2p itinerant electron model.