Theoretical and numerical analysis of the effective medium properties of a ferromagnetic microwire lattice

Abstract

Effective medium properties of a 3D-lattice consisting of an infinite number of ferromagnetic microwires are theoretically and numerically analyzed in the presented work. All microwires are considered to be embedded in free space, parallel to one another and a constant magnetic field ${\mathbf{\text{H}}}_{\mathbf{\text{0}}}$ is applied to the whole composite sample along the axis of microwires. The local and average fields are computed within a unit cell, by solving the scattering problem through satisfying the tangential boundary conditions. Hence, effective permittivity and permeability are analyzed within a unit cell. Field dependent permittivity and permeability characteristics are observed due to a high sensitivity of the ac surface impedance of a ferromagnetic wire to a magnetic field. Effects of the operating frequency, radius of microwires, microwire spacing and applied external magnetic field ${\mathbf{\text{H}}}_{\mathbf{\text{0}}}$, on the effective medium properties are discussed in detail. Numerical results are simulated only for $T{M}_z$ polarization for normal incidence. Validation is done through the comparison of proposed numerical results with the results available in the literature for ${ϵ}_{zz}^{\mathrm{eff}}$.

Keywords:

• Effective permittivity
• effective permeability
• ferromagnetic microwires
• ferromagnetic resonance
• magnetoimpedance
• metamaterials
• scattering

Disclosure statement

No potential conflict of interest was reported by the author(s).