Spectrum of spin waves propagating in a periodic magnetic structure

In this paper, an analytical expression for the spectrum of propagating spin waves (SW) in a periodic multilayer ferromagnetic structure is obtained using Landau-Lifshitz (LL) equations. A graphical approach by which to study the influence of the modulation of many material parameters on character of SW propagation is proposed. New effects due to both the bias magnetic field and the joint modulation of several magnetic parameters of the structure are discovered. Namely, the parameters can be chosen so that the SW spectrum of the magnetic multilayer in a certain bias field will not contain band gaps. A slight misbalance of the system causes the appearance of the latter. The effect of dissipation on the results obtained as well as the possibility of their application is discussed. (C) 2003 Elsevier B.V. All rights reserved.