Stop bands and defect modes in a magnonic chain of cells showing single-cell spectral gaps

Abstract

A magnonic chain of cells consisting of a serial loop structure with dangling resonators (SLS-DRs) is designed to obtain possibly large stop bands. Contrary to all known systems of this kind, a spectral gap of nonzero width occurs here even with a single cell. General expressions for the dispersion relation and for the transmission coefficient are given for all serial systems of this kind within the framework of the long-wavelength Heisenberg ferromagnetic model. The width of the stop bands is very sensitive to the number of resonators and may be drastically increased in a tandem geometry made of several successive SLS-DRs which differ by their geometrical characteristics. These SLS-DRs may have potential applications in spin injection into devices.