Cation distribution and micro level magnetic alignments in the nanosized nickel zinc ferrite

Abstract

Ni0.5Zn0.5Fe2O4 nanoparticles were synthesized through sol–gel synthesis method. Sintering at elevated temperatures was employed to obtain samples with higher particle sizes. The structural characterization using X-ray diffraction suggests that the three samples possess uniformal cation distribution. The variation of magnetization as a function of applied magnetic field at room temperature is studied using a vibrating sample magnetometer and all the samples found to exhibit nearly zero remanence and zero coercivity suggesting a superparamagnetic behaviour. The variation of magnetizations of the three different samples with temperature was studied by ZFC–FC technique at two different applied fields of 10Oe and 1000Oe. In order to study the possibility of structural changes, chemical and coordination differences of iron in the nanocrystalline Ni–Zn ferrite particles, room temperature 57Fe Mössbauer spectroscopy study was used. The application of 5T magnetic field at 5K temperature resolves the two sub spectra and canting angle of 27o and 12o were observed which clearly indicates the noncollinear magnetic alignment in nano crystallites of Ni0.5Zn0.5Fe2O4. The neutron diffraction study was performed at seven different temperatures 20, 50, 100, 150, 200, 250 and 300K. Rietveld refinement of the neutron diffraction data was performed to deduce the basic structural parameters, cation distribution and micro level magnetic alignments in the nanosized nickel zinc ferrite.