Synthesis of copper-magnesium-zinc ferrites and correlation of magnetic properties with microstructure

A novel route for the preparation of high density, high permeability Cu-Mg-Zn ferrites using oxalate precursors is reported, with various Mg2+ contents represented as Cu(0.5-x)MgxZn0.5Fe2O4 wherein x = 0.00, 0.20, 0.25, 0.40. To investigate the ferritization temperature of this system, TG/DTG/DTA studies have been carried out varying from 599 to 743 K with increasing x. X-Ray diffraction (XRD) study revealed that all the samples had a single spinel phase and the cubic lattice parameter 'a' decreased with an increase in x. Particle size distribution (PSD) and scanning electron microscopy (SEM) techniques were employed to determine the average particle size and to study the microstructure respectively. Initial permeability of all the samples increased with increase in temperature and Mg2+ content (x less than or equal to 0.20). It also exhibited a thermal hysteresis effect. The magnetic properties are correlated with high density and grain structure. The magnetic properties of this ferrite system prepared by novel route are superior to those of commercial ETKMG ferrites. (C) 1999 Elsevier Science S.A. All rights reserved.