Magnetic nanocomposites at microwave frequencies

TL;DR

This paper reviews the magnetic properties of nanocomposites with magnetic nanoparticles embedded in dielectric matrices, introduces a new measurement method for their electromagnetic characterization, and presents experimental results on iron nanoparticle composites.

Contribution

It provides a comprehensive review of magnetism theory in nanocomposites and introduces a novel measurement technique for their electromagnetic properties.

Findings

Nanocomposites exhibit low losses due to single-domain nanoparticles.

Experimental results show promising electromagnetic properties of iron nanoparticle composites.

The measurement method enhances characterization accuracy for nanomagnetic materials.

Abstract

Most conventional magnetic materials used in the electronic devices are ferrites, which are composed of micrometer-size grains. But ferrites have small saturation magnetization, therefore the performance at GHz frequencies is rather poor. That is why functionalized nanocomposites comprising magnetic nanoparticles (e.g. Fe, Co) with dimensions ranging from a few nm to 100 nm, and embedded in dielectric matrices (e.g. silicon oxide, aluminium oxide) have a significant potential for the electronics industry. When the size of the nanoparticles is smaller than the critical size for multidomain formation, these nanocomposites can be regarded as an ensemble of particles in single-domain states and the losses (due for example to eddy currents) are expected to be relatively small. Here we review the theory of magnetism in such materials, and we present a novel measurement method used for the characterization of the electromagnetic properties of composites with nanomagnetic insertions. We also present a few experimental results obtained on composites consisting of iron nanoparticles in a dielectric matrix.