EFFECT OF EVOLVING MICROSTRUCTURE ON MAGNETIC PROPERTIES OF NOMINAL MG0.45ZN0.5CU0.05 FERRITE

Abstract

In this work, we report on the evolution of the microstructure magnetic property relationship in MgZnCu ferrites with composition Mg0.45Zn0.5Cu0.05 Fe2O4 applicable for producing an industrial ferrite product. The starting powders MgO, ZnO, CuO and Fe2O3 were mechanically alloyed for 10 hours in order to obtain nanometer size starting powder and formed into toroidal shape. The MgZnCu ferrite toroidal samples with nanometer size were then sintered from 600°C up to 1100°C with 100°C increments. The phase and surface morphology of the toroidal were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. The variation of the complex permeability was measured using an Agilent HP4291A Impedance Analyzer in the range of 1MHz to 1.0GHz. The saturation magnetization was determined from a B-H loop which was obtained via a MATS 2010SD Static Hysteresis graph. The average grain size of a sintered sample was measured over 200 grains by the linear intercept method. It was found that the average grain size increased from 0.014 µm to 1.017 µm. This indicated the microstructure evolution of the samples. The XRD patterns show that every single diffractogram contained multiple-phases due to the effect of copper addition into ferrites in nanostructures. The permeability decreased due to presence of pores and intergranular pores provides the impediment to the domain wall displacement and caused a decrease in permeability. The density, grain size, resistivity and saturation magnetization of all the samples increased with the sintering temperature. Materials can be widely used in electronic circuit in a frequnecy range from 8 to 10 MHz.