Synthesis and magnetic properties of Ni-Zn ferrite @polyaniline/epoxy composites for embedded inductor applications

The development of the electronic industry and electronic technology is proceeding in the direction of miniaturization and high frequency. The embedded passives technology, as a key technology in system-in-package mode, throws new light on improving the package of the passives. Much works have been done to develop embedded passives. For inductors, Ni-Zn ferrites with soft magnetic are ideal materials for preparing the magnetic composite materials. In this study, Ni-Zn ferrite was prepared by a chemical coprecipitation method, then was oxidative polymerization of aniline in aqueous solution and made the Ni_0.5Zn_0.5Fe₂O₄@polyaniline (NZF@PANi) core-shell particles. The obtained particles were characterized by X-ray diffraction (XRD). The magnetic epoxy composites were fabricated by mixing the core-shell particles and epoxy resin matrix. The dielectric and magnetic properties of the composites were measured by impedance analyzer (Agilent E 4991 A: 1 MHz to 1 GHz). The initial complex permeability value obtained from the toroidal sample exhibit good frequency stability and the permeability loss was low. The permeability of the epoxy composite was rising from 1.4 to 2.2 with the mass fraction of the ferrite increasing in the composite from 3%-70%.