Abstract: This paper investigates the effects of dopant on sintering and the properties of NiZnCu ferrite. There are marked changes in the microstructures of Ni_0.3Zn_0.7Cu_0.04Fe_2.04O_4+δ doped with various Nb₂O₅ contents.It is possible that the change in the microstructure is the main reason for the variations of other properties.The-experiments reveal that Nb₂O₅ can improve the sintering process and protect the-grain from enormous growth, Nb⁵⁺ ion can influence the lattice parameter,resistivity, density, initial permeability and magnetic loss.

Key words: Nb₂O₅, NiZnCu ferrite, microstructure, ferrite