Effects of MnO2 on the electromagnetic properties of NiCuZn ferrites prepared by sol-gel auto-combustion

Mn-doped NiCuZn ferrites with compositions of (Ni0.2Cu0.2Zn0.6)O(Fe2-xMnxO3 )(0.98) (x=0, 0.02, 0.04, 0.06) were prepared by a novel sol-gel auto-combu stion process. The synthesized nano-sized ferrite powders can be sintered a t 900 degreesC, and the sintered ferrites are characterized by fine-grained microstructural feature and high permeability. Mn content in formulations largely affects the grain size and main electromagnetic properties of sinte red NiCuZn ferrites. With increasing Mn content. the initial permeability i s significantly increased, while the electrical resistivity and quality fac tor are decreased. The dielectric constant and dissipation factor are also affected by the incorporation of MnO2. The possible mechanism for the influ ence of MnO2 on the electromagnetic properties was discussed. (C) 2001 Else vier Science B.V. All rights reserved.