Random copper/yttrium iron garnet composites with tunable negative electromagnetic parameters prepared by in situ synthesis

Abstract

Negative parameter materials (NPMs) with negative permittivity and/or negative permeability have attracted increasing attention in recent years. In this work, the tunable negative electromagnetic parameters of copper/yttrium iron garnet (Cu/YIG) composites, which were prepared by an in situ synthesis process, were investigated in a radio frequency regime. When they reached the percolated state, Fano-like resonances are observed and the permittivity changes from negative to positive. In addition, the combined contributions of the magnetic resonance of ferrimagnetic YIG particles and the diamagnetic response of the current loop bring about negative permeability in high frequency. Furthermore, the negative permittivity and permeability could be controllable by an external magnetic field. Hopefully, it is indicated that the in situ synthesis process offers a facile and versatile approach to fabricate NPMs.