Effect of Bi2O3 and V2O5 addition on Structural, Electrical transport and Electromagnetic properties of Ni-Cu-Zn Ferrites

Abstract

Ni-Cu-Zn ferrites are well-known technological magnetic materials used for manufacturing of multilayer chip inductor and applications in various electrical devices. The present work is focused on the influence of substitutions and sintering additive V2O5 and Bi2O3 on structural, transport and electromagnetic properties of NiCu-Zn ferrites. Two series of ferrite samples of the composition Ni0.28Cu0.10Zn0.62Fe2O4 + x wt.% the concentration sintering additives were varies 0.2wt.% to 0.8wt.% for (i) V2O5 and (ii) Bi2O3 were prepared by using the solid state reaction technique sintered at 1150oC and 1200oC with 6 hours holding time. The Xray diffraction analysis revealed that all the samples of the two series are crystalline in single phase cubic spinel structure. Lattice parameter of Ni0.28Cu0.10Zn0.62Fe2O4 + x wt.% V2O5 or Bi2O3 are slightly decrease with the increase of x content. The average grain size of the samples increases with the increase of V2O5 additive content. On the other hand grain growth by increasing Bi2O3 content inter diffusion as results after > 0.4wt.% Bi2O3 content abnormal grain growth. Curie temperature (Tc) and saturation magnetization (Ms) are slightly increase with increasing V2O5 doped ferrite samples up to x = 0.6 after decrease. On the other hand Tc decreases continuously with the increase of Bi2O3 additive in the same ferrite samples. The magnetization process all the samples are soft magnetic behavior. Initial permeability (µi) increases with the increase of V2O5 at both sintering temperatures attaining maximum value for x = 0.4. This enhancement of permeability may be correlated with improved microstructural features. But the µi decreases with increasing doped Bi2O3 content in ferrite samples and hence the highest value of quality factor is found for x = 0.4 within the range 20kHZ to 2MHz. The µi shows a flat profile from 1kHz to 4MHz indicating frequency stability for all the ferrite samples. The improved electromagnetic properties of the composition might be attributed to better densification and visible grain size. DC resistivity decreases with increasing temperature. The dielectric constant is found to decrease continuously with increasing frequency and remain almost constant at higher frequency range. The dielectric behavior of the experiment ferrite samples explained on the basis of the mechanism of the dielectric polarization and conduction process.