Effect of cation distribution on the magnetic and hyperfine behaviour of nanocrystalline Co doped Ni–Zn ferrite (Ni 0.4 Zn 0.4 Co 0.2 Fe 2 O 4 )

Abstract Nanoparticles of Ni0.4Zn0.4Co0.2Fe2O4 are prepared by a simple co-precipitation method. The as dried sample is heat treated at 400, 500, 600, 700 and 800 °C to obtain different sizes of nanoparticles. The crystallographic phase of the samples is confirmed analyzing observed X-ray diffraction (XRD) by Rietveld method. Hyperfine parameters of the samples are derived from room temperature (RT) Mossbauer spectra of the samples. Magnetic properties of the samples are investigated by static and dynamic hysteresis loops. Different magneto-crystalline parameters are calculated from the variation of magnetization with temperature (M–T curve) under zero field cooled (ZFC) and field cooled (FC) conditions of the as dried sample. The cation distribution estimated from Rietveld analysis are correlated with the results of magnetic and Mossbauer effect measurements. The observed high value of saturation magnetization (72.7 emu/g at RT) of the sample annealed at 800 °C would be interesting for applications in different electromagnetic devices.