Tunable metacomposites containing hybrid Co- and Fe-based ferromagnetic microwires

Abstract

Metamaterials have attracted tremendous research interest due to their fascinating unusual properties that are not available from nature, such as negative refractive index, reverse Doppler Effect, negative compressibility, etc. [1]. However, conventional metamaterials are simply structures as their special properties are independent to intrinsic properties of building blocks, which tarnishes their application perspectives to a large extent. Ferromagnetic microwires have been reported feasible to create electromagnetically double negative (DNG) medium by arranging them in a parallel [2] and orthogonal manner [3]. Recently we proposed the concept of metacomposites containing Fe-based microwires and revealed their DNG properties in line with advantages such as structural integrity and economic processing over metamaterials [4, 5]. Herein, as a step further, metacomposites containing hybrid Co- and Fe-based microwire arrays with different topology are designed and fabricated. A tunable DNG feature under external dc magnetic field is observed in the metacomposite containing continuous wire arrays evidenced by transmission windows and a negative dielectric permittivity dispersion. A DNG/band stop characteristic is observed in the metacomposite containing short-cut wires confirmed by a dip at 6 GHz in the transmission spectrum.