Zn,Ni ferrite/NiO nanocomposite powder obtained from acetylacetonato complexes

Abstract

The results on the synthesis, microstructure, structure and DC magnetization studies ofnanocomposite Zn,Ni ferrite/NiO powder obtained by thermal decomposition ofacetylacetonato complexes are reported in this paper. According to the resultsobtained by inductively coupled plasma optical emission spectroscopy (ICP-OES)element analysis and multiphase Rietveld refinement, the three samples made arecomposed of spinel-ferrite (86.7%–96.7%) and NiO (3.3%–13.3%) phases. Thecompositions of the spinel-ferrite (SP) phase in the investigated samples, S1–S3, areZn0.72Ni0.24Fe1.98O4,Zn0.56Ni0.29Fe2.07O4 and Zn0.40Ni0.40Fe2.10O4, respectively. Due to the cation deficiency in spinels, created vacancies induce a partialchange in the cation valence, . The vacancy distribution is found to be random at 8a and 16d cation sites, except insample S3, where all vacancies are over octahedral sites. The x-ray line broadening dueto crystallite size effect is found to be isotropic for all spinels, while the x-rayline broadening due to the strain effect is anisotropic. A correlation between theZn2+ occupancy of thetetrahedral site and the 650 cm−1 Raman peak intensities is shown. The observed coercivity decrease and shift in hysteresis loopin the samples are caused by the interaction between spinel and NiO phase. The results ofM(H) measurements point to the properties of an ensemble of interacting nanoparticles. Highsaturation magnetization values and superparamagnetic behaviour at room temperaturepoint to the technological significance of the title compounds.