Structural and magnetic properties of nanoparticle Mn-Zn-Ni ferrite powders grown by using a sol-gel method

摘要

Nanoparticle Mn-Zn-Ni ferrite powders, Mn_(1-2x)Zn_xNi_xFe_2O_4 (0. 0 ≤ x ≤ 0. 3), were fabricated using the sol-gel method, and their structural and magnetic properties were investigated. Using X-ray diffraction and M?ssbauer spectroscopy, we confirmed the formation of crystallized particles annealed at 523 K. All the Mn-Zn-Ni ferrite powders showed a single phase with a spinel structure. The size of the ferrite powders grains increased as the rate of Zn and Ni substitution was increased. The M?ssbauer spectra for x ≥ 0. 1 in Mn_(1-2x)Zn_xNi_xFe_2O_4 could be fitted by superposition of two Zeeman sextets and one doublet due to the ferrimagnetic and the superparamagnetic phases. However, for x = 0. 0, the M?ssbauer spectrum could be fitted to one doublet due to the superparamagnetic phase. From the variation of the M?ssbauer parameters and the absorption area ratio, the cation distributions were determined. In the Mn_(1-2x)Zn_xNi_xFe_2O_4 powder samples, the coercivity increased from 41. 66 Oe for x = 0. 0 to 49. 87 Oe for x = 0. 3 as the rate of substitution was increased, but the saturation magnetization showed a maximum value of 29. 26 emu/g for x = 0. 2.