Study of magnetic properties of NiZnCu ferrite synthesized by Pechini method and solid-state reactions

Gaëlla Frajer,Olivier Isnard,Gérard Delette,Mathieu Salaün,Hervé Chazal

doi:10.1063/1.4994035

Abstract

Ni-Zn-Cu ferrites are exhibiting excellent magnetic properties at large frequencies and are consequently produced as low-loss magnetic materials used for magnetic components in power electronics. Here we present an experimental study of (Ni0.31Zn0.49Cu0.20)0.979Co0.021Fe1.9-dO4 ferrites synthesized by the Pechini type sol-gel method. Their structural and magnetic properties are characterized and compared to the ones of reference ferrites synthesized by classical solid-state reactions. Optimized parameters for Pechini method allow obtaining comparable low magnetic core-losses for both synthesis methods. The cores obtained by this sol-gel method present higher static permeability and lower coercive field than the ones obtained by classical solid-state reactions. Results suggest that the microstructure of ferrites synthesized by Pechini method can be considered as a promising alternative route for the design of low-loss magnetic components.

Highlights

Ni-Zn or Ni-Zn-Cu ferrites are exhibiting excellent magnetic properties at high frequencies above 1 MHz
Energy dissipation by domain wall motions is reduced and dynamic magnetization occurs mainly by spin rotation leading to low core-losses at high frequency
Even if some oxides remain in the post-calcination powder, the ferrite phase is completely formed after sintering for all synthesis methods

Summary

Introduction

Ni-Zn or Ni-Zn-Cu ferrites are exhibiting excellent magnetic properties at high frequencies above 1 MHz. Cobalt cation can induce locally a large anisotropy that tend to stabilize the domain wall in large grains and prevent further displacement (acting as a pinning defect).[3,4,5,6] Energy dissipation by domain wall motions is reduced and dynamic magnetization occurs mainly by spin rotation leading to low core-losses at high frequency It was highlighted by Lucas et al that the core-losses of cobalt substituted ferrites depend on the temperature and are maintained low at around 80◦C (typical working temperature of power converters).[7]

Methods

Results

Conclusion