High-Frequency and Microwave Magnetic Properties of Ni$_{0.5}$Zn$_{0.5}$Fe$_2$O$_4$ Spinel Ferrite Ceramics

TL;DR

This study investigates the high-frequency magnetic properties of NiZn ferrite ceramics, revealing temperature-dependent resonance behaviors and magnon excitations that enable effective electromagnetic shielding in the GHz range.

Contribution

It provides new insights into the magnetic resonance and magnon dynamics of NiZn ferrite ceramics across a broad frequency spectrum, highlighting their potential for 5G and 6G communication applications.

Findings

Strong temperature-dependent permeability dispersion observed from 10 MHz to 2 GHz.

Identification of three magnon excitations in the microwave range.

High absorption and shielding efficiency at GHz frequencies.

Abstract

Magnetic properties of the Ni$_{0.5}$Zn$_{0.5}$Fe$_2$O$_4$ (NZF) spinel ferrite ceramics were studied over a broad frequency range (1 MHz - 50 GHz). Between 10 MHz and 2 GHz, strong temperature-dependent resonance-like magnetic permeability dispersion was observed and attributed to the magnetic domain-wall dynamics. It is responsible for the high magnetic losses, absorption and shielding ability of NZF, and provides high nonlinearity and tunability of the permeability under a weak magnetic field. The attenuation constant of NZF is comparable to those of dielectric-conductor composites and giant permittivity materials. In the microwave range (2-50 GHz), three magnetic excitations dependent on a weak magnetic field were revealed and related to magnons. The lowest-frequency magnon (<10 GHz) is attributed to the natural ferromagnetic resonance, two others are excited between 28 and 44 GHz. Interaction of the magnons and magneto-dielectric resonance modes with electromagnetic waves provides high absorption and shielding efficiency in the GHz range, including 5G and 6G communication frequencies.