Rapid synthesis of nickel ferrite nanoparticles by the molten salt method

It is presented a 'shocking thermal treatment' methodology as a modification to the molten salts process to rapidly obtain pure phase nickel ferrite nanoparticles within a high-scalable green synthesis scheme. Analysis from x-ray diffraction and electron microscopy (SEM andTEM) confirms the formation of the nanostructures, with the most frequent crystallite sizes between 55-85 nm. Room temperature magnetic characterization, from Mossbauer spectroscopy and magnetic measurements M(H), evidences their superparamagnetic distribution with a magnetic saturation of 47.9 emu g(-1). An approximated stoichiometry of (Ni0.03Fe0.97)A(Ni0.97Fe1.03)BO4 was proposed fromRietveld refinement, Mossbauer and energy-dispersive x-ray spectroscopies. The effect on the electronic structure due to the shocking thermal treatment was elucidated by estimating the optical band gap with values between 1.78 and 2.38 eV.