Effects of heat treatment conditions on the structural and magnetic properties of MgCuZn nano ferrite

Mg0.5Cu0.05Zn0.45Fe2O4 nanoparticles were prepared through sol-gel method using polyvinyl alcohol as a chelating agent. The as prepared sample was annealed at three different temperatures (500 degrees C, 700 degrees C and 900 degrees C). The phase formation, morphology and magnetic properties with respect to annealing temperature were studied using the characterisation techniques like X-ray diffraction (XRD) as well as Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and vibrating sample magnetometer (VSM), respectively. The crystallite size and magnetisation showed increasing trend with annealing temperature. The coercivity increased up to a particular annealing temperature and decreased thereafter, indicating transition from single domain to multi domain state with increasing annealing temperature. Further, to know the suitability of the material, as a ferrite core, in multilayer chip inductors, the powder sample annealed at 500 degrees C was compacted in the form of torroids and sintered at three different temperatures (800 degrees C, 900 degrees C and 950 degrees C). The permeability showed increasing trend with the increase of sintering temperature since the permeability depends on microstructure. The frequency dispersion of permeability, for the sintered samples, demonstrated high frequency stability as well as high operating frequency. The cut-off frequency for the sintered samples 800 degrees C, 900 degrees C and 950 degrees C is 32 MHz, 30.8 MHz and 30.4 MHz, respectively. (c) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.