Spin‐wave spectra and magnetization of ferro–ferrimagnetic double layers

Abstract

The spin‐wave spectra and magnetization of the ferro–ferrimagnetic double layers are studied by using a linear spin‐wave approximation and retarded Green's‐function method. We obtain the four branches of the spin‐wave spectra. Two energy gaps are found to exist in the energy band. The effects of the interlayer exchange coupling, the intralayer exchange coupling and the spin quantum numbers on the spin‐wave spectra and the energy gaps are discussed. The minimum (maximum) value point on the spin‐wave spectra and energy gaps correspond to a system that has a high symmetrical magnetic structure and the balance of quantum competitions among the exchange couplings and the spin quantum numbers of the system. There is a crossover between sublattice magnetizations in ferromagnetic layer that is affected by quantum fluctuations, thermal fluctuations and frustration of spins. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Spin-Wave Modes in Exchange-Coupled FePt/FeNi Bilayer Films

“…Jiang et al theoretically predicted the existence of multiple possible spin waves in such bilayer films. [12] Monteiro et al [13] have also theoretically shown, by simulations, that an inhomogeneous internal magnetic field, caused by the exchange field between hard and soft magnetic layers, does exist in exchange-coupling region within an FePt/Fe bilayer system. They also predicted that rich spin-wave modes related to the variation of the local effective magnetic field across Fe layer exist in the exchange-coupling films.…”