Chapter 6 - One-dimensional magnonic crystals
Résumé
This chapter presents examples of bulk and surface magnons of one-dimensional magnonic crystals, called also superlattices. The such man-made crystals considered here are grown out of semiinfinite stacks of two and also three different ferromagnetic slabs. Each slab is modeled by a simple cubic lattice of spins coupled via nearest-neighbor exchange interactions. Such crystals have a larger periodicity in the direction perpendicular to the slabs and therefore many magnon branches in the folded Brillouin zone. In gaps existing between these bulk magnon branches appear the surface magnons. The tutorial simplicity of this model allows to obtain in closed form the bulk and the (001) surface response functions for such crystals. These functions enable then to obtain in closed form the folded bulk magnons and also the surface modes within the gaps. Two figures illustrate these results.