Normal mode theory for magnonic crystal waveguide

Abstract

A general theory for dipole-exchange spin-wave spectrum of magnonic crystal waveguide has been developed. Magnonic crystal waveguide is assumed to be a thin-film ferromagnetic waveguiding medium with periodical modulation of the magnetic parameters along the spin-wave propagation direction. The periodical variation of the magnetic parameters is taken into account in the framework of the Floquet theorem for a differential equation with periodic coefficients. The spin-wave modes' approach, together with the method of tensorial Green's functions, is used to describe propagating spin waves. The exact dispersion relation is obtained in the form of an infinite determinant, which can be easily reduced to a finite one for each particular problem under consideration. © Springer-Verlag Berlin Heidelberg 2013.