Effect of copper on the electromagnetic properties of Mg-Zn-Cu ferrites prepared by sol-gel auto-combustion method

A novel gel auto-combustion method was used to synthesize Mg-Zn-Cu ferrite powders with compositions of (Mg0.5-xCuxZn0.5)O(Fe2O3)(0.98) (where x = 0.2 0, 0.25, 0.30, 0.35, 0.40). X-ray diffraction results showed that the dried gels, synthesized from metal nitrites and citric acid, transformed directl y into nano-sized ferrite particles after an auto-combustion process in air . The synthesized powders exhibited high-sintering activity, and can be sin tered at temperature less than 950 degreesC. The low-temperature sintered M g-Zn-Cu ferrites prepared possess good electromagnetic properties, as well as fine-grained micro structures, making them become good materials for mul tilayer chip inductors with high-performance and low-cost. Copper content h as significant influence on the electromagnetic properties, such as initial permeability, quality factor, DC resistivity, dielectric constant and diel ectric loss tangent as well as their frequency dispersion for Mg-Zn-Cu ferr ites. The possible reasons that are responsible for the composition depende nce of main electromagnetic properties were discussed. (C) 2001 Elsevier Sc ience B.V. All rights reserved.