Synthesis, structural and electrical characterization of Sb substituted spinel nickel ferrite (NiSbxFe2−xO4) nanoparticles by reverse micelle technique

Spinel nickel ferrite with nominal composition NiFe_2−xSb_xO₄ (where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1) has been synthesized by the reverse microemulsion method. The samples synthesized were characterized by XRD, FTIR, TGA/DTGA, SEM, AFM, Mossbauer Spectroscopy and DC electrical resistivity measurements. The XRD analysis confirmed the formation of single spinel phase and the crystallite size was found to be in the range of 8-38 nm. The particle size of the synthesized samples was also confirmed by the AFM and SEM which was found in the range of 5-45 nm and 10-45 nm, respectively and this size is small enough for obtaining the suitable signal-to-noise ratio in high density recording media. The Mossbauer spectra of samples showed two well-resolved Zeeman patterns corresponding to A and B sites and also observed a doublet at higher substitution. The DC electrical resistivity showed an interesting behavior with temperature and observed a metal-to-semiconductor transition temperature (T_M-S) which suggests that the material can be applied for switching applications. The resistivity increases with the increase in Sb-content and it suggests that the material can be fruitfully used for applications in microwave devices.