Synthesis and Magnetic Properties of New Multi-components Spinel Ferrite Nanoparticles

We synthesized new multi-components spinel ferrite including Ni, Mn, Zn, Co, and Fe in order to improve the magnetic properties in nanosized particles by using a chemical coprecipitation method. The samples were synthesized in the mole ratios of M_xM_yFe_{(1_x+y)}OldrFe₂O₃ (M_x M_y=Ni, Mn, Zn, Co, 0<M_x+M_y<1), and the maximum saturation magnetizations of them were measured by VSM. XRD patterns of M_xM_yFe_(1-x+y)OldrFe₂O₃ nanoparticles showed spinel structure and it was observed by EPMA that the composition of nanoparticles was about the same as stoichiometry of the starting materials. Each maximum saturation magnetization of synthesized samples was 66.1 ~ 83.3 [Aldrm²/kg]. The saturation magnetizations of the samples including Zn²⁺ have increased prominently. CoZnFeO-Fe₂O₃ nanoparticles showed the highest saturation magnetization. The relevant mole ratio of CoZnFeO-Fe₂O₃ was investigated, and the mean diameter of CoZnFeO-Fe₂O₃ nanoparticles was determined by TEM image. The change of mole ratio affects the saturation magnetization of CoZnFeO-Fe₂O₃ nanoparticles, which ranges from 2.6 to 83.3 [Aldrm²/kg]. Co_0.21Zn_0.17Fe_0.62OldrFe₂O₃ particles had maximum saturation magnetization of 83.3 [Aldrm²/kg]. The particle size decreases with the increase in mole ratio of Co²⁺ and it ranges from 7.8 to 11.3 [nm]. The results indicated that the variation of saturation magnetization was larger than that of the particle size. The saturation magnetization of Co_0.21Zn_0.17Fe_0.62OldrFe₂O₃ (83.3 [Aldrm²/kg]) increased by 31%, compared with that of FeO-Fe₂O₃- (63.8 [Aldrm²/kg]). We succeeded at improving the magnetic properties in nanosized particles by synthesizing multi-component spinel ferrite.