Interface Effective Pinning and Dynamical Coupling of Spin Waves in Bilayer Ferromagnetic Films with Canted Magnetizations
H. Puszkarski and M.G. Cottam
Centre for Chemical Physics and Department of Physics, University of Western Ontario, London, Ontario, Canada N6A 3K7
Received: May 31, 1990
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We present a theory for the spin-wave excitations in bilayer magnetic systems with exchange coupling across the interface between two ferromagnetic films having the same crystallographic structure. The Hamiltonian includes exchange and anisotropy terms within each magnetic film of the composite system, as well as at the interface and at the free surfaces. We examine, in particular, the effect of interface canting between the magnetization directions for each film, and we derive effective pinning parameters and dynamic coupling parameters for the interface as functions of the canting angle. We show that, in the special case when the magnetization directions are antiparallel in the bilayer system, the two films may be considered as effectively decoupled as regards the spin-wave dynamics. We discuss the relevance of this theory to recent experimental studies of bilayer ferromagnetic systems that exhibit antiferromagnetic interface exchange.
DOI: 10.12693/APhysPolA.79.549
PACS numbers: 75.70.Cn, 75.30.Ds