Electrodynamic model for low loss microwave nanocomposite magnets using autonomous blocks with Floquet channels

Abstract

The diagonal and off-diagonal components of the effective permeability tensor and the effective permittivity of three-dimensional (3D) periodic magnetic nanosystems, depending on the size and separation of the magnetic nanoparticles, were calculated using the computed values of the propagation constants and the dispersion relations of clockwise and counterclockwise polarized electromagnetic waves (EMWs), as well as for the ordinary and extraordinary modes in the gyromagnetic medium. The propagation constants of EMWs in a 3D periodic array of 150 nm iron nanospheres in a dielectric matrix, depending on the ratio of the period of the array to the radius of the nanospheres, were obtained at a frequency f=30 GHz for longitudinal and transverse orientations of the bias magnetic field. It is shown that the magnetic and dielectric losses of weakly interacting systems are lower than that of yttrium iron garnet (YIG); however, losses increase due to spin wave (SW) excitations upon reduced separation.