# Flexible Ferrite Magnetic Composite Films for Electromagnetic Applications

## TL;DR

Flexible magnetic films with improved performance are created by modifying ferrite particles and adding FeNi alloy, promising for advanced electronic applications.

## Contribution

A novel composite film with enhanced magnetic properties through surface modification and FeNi alloy integration is developed.

## Key findings

- Surface modification with SiO2 and silane improves particle dispersion and magnetic anisotropy.
- Adding FeNi alloy particles increases saturation magnetization and permeability.
- Hybrid films show improved inductance and quality factor for inductor applications.

## Abstract

Anisotropic magnetic composite films composed of MnZn
ferrite powders
embedded in an epoxy matrix are investigated for flexible thin-film
inductor applications. Commercial MnZn ferrites typically contain
α-Fe2O3 impurities that impair magnetic
performance; in this study, these impurities are effectively eliminated
by thermal annealing at 600 °C under argon. To improve particle
dispersion and processability within the composite, the ferrite is
surface-modified with 3-glycidoxypropyltrimethoxysilane and coated
with SiO2, yielding a more dispersible MZ@SiO2. This treatment enables the formation of well-aligned particle chains
under an external magnetic field, resulting in pronounced magnetic
anisotropy and stable permeability. Incorporating FeNi alloy particles
into the MZ@SiO2-based films further increases saturation
magnetization and permeability, though finite element simulations
indicate that the performance of larger FeNi particles is relatively
insensitive to orientation. Inductor devices fabricated with the hybrid
MZ@SiO2–FeNi films exhibit improved inductance and
quality factor, underscoring their promise for next-generation high-performance
magnetic components with tunable anisotropy.