Magnetic property and cation distributions in boron-doped MFe2O4(M = Ni, Mn) spinel ferrites

Abstract (A)[B] 2 O 4 spinel ferrites with initial compositions, Bx M 1− x Fe 2 O 4 ( 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 B x 1 M x 2 Fe 3− x 1− x 2 O 4 ( 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, x 1 , 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 Mn 3+ 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.