Spinel ferrite nanoparticles plays important role in many applications due to their excellent structural, magnetic and electrical properties. Among the spinel ferrite nickel ferrite is a prominent candidate for various applications and is the subject of interest to many researchers. Therefore, attempt is made to synthesize NiFe2O4 nanoparticles and investigate its structural, infrared and magnetic properties for high frequency applications. NiFe2O4 nanoparticles were synthesized by sol-gel auto-ignition technique. Efforts are made to obtain nanopowder of high quality by taking extra care and some modification in synthesis procedure. In order to examine the phase purity and nanocrystalline nature, prepared nanopowder was subjected to X-ray diffraction studies. A close examination of XRD pattern revealed the presence of the reflections belonging only to cubic spinel structure. No extra peak was seen in the XRD pattern. The crystallite size was estimated using Debye-Scherrer’s formula and found to be 22nm. FT-IR spectrum of NiFe2O4 shows the two prominent absorption bands near the frequency range 400 cm−1 and 600 cm−1. The important magnetic property was studied by M–H plot which was recorded using pulse field hysteresis loop tracer at room temperature. Using the M-H plots the values of saturation magnetization, coercivity, and remanence magnetization are recorded as 37.61 emu/g, 177 Oe, and 11.71 emu/g respectively. The obtained data for structural and magnetic properties will be useful for high frequency applications.

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In the present study we report the synthesis of cobalt ferrite nanoparticles using one of the well-known wet chemical method i.e. sol-gel auto combustion technique. The synthesis was carried out at sufficiently low temperature of 100°C. Citric acid was used as a fuel in the synthesis process. The obtained nanoparticles were sintered at 550°C for 4 h and then used for structural and magnetic investigations. The phase pure nature and nano crystalline nature was investigated through X-ray diffraction technique. Room temperature X-ray diffraction pattern show well defined reflections oriented at different Bragg’s angle corresponding to Miller indices (220), (311), (222), (400), (422), (511) and (440). All this reflections belongs to cubic spinel structure. Thus, XRD analysis confirms the formation of single phase compound. The particle size was obtained through Scherrer’s equation and found to be 21 nm, indicating the nanocrystalline nature. The magnetic properties were investigated using pulse field hysteresis loop tracer at room temperature. The saturation magnetization show increased values as compared to the bulk cobalt ferrite. The coercivity found to be less which exhibits the superparamagnetic behaviour. The obtained structural and magnetic parameters are useful in biomedical applications.