  We investigate the effect of coupling (intensity and nature), applied field,
and anisotropy on the spin dynamics of a multi-layer system composed of a hard
magnetic slab coupled to a soft magnetic slab through a nonmagnetic spacer. The
soft slab is modeled as a stack of several atomic layers while the hard layer,
of a different material, is either considered as a pinned macroscopic magnetic
moment or as an atomic multi-layer system. We compute the magnetization profile
and hysteresis loop of the multi-layer system by solving the Landau-Lifshitz
equations for the net magnetic moment of each (atomic) layer. We study the
competition between the intra-layer anisotropy and exchange interaction,
applied magnetic field, and the inter-slab exchange, dipolar or
Dzyaloshinski-Moriya interaction. Comparing the effects on the magnetization
profile of the three couplings shows that despite the strong effect of the
exchange coupling, the dipolar and Dzyaloshinski-Moriya interactions induce a
slight (but non negligible) deviation in either the polar or azimuthal
direction thus providing more degrees of freedom for adjusting the spin
configuration in the multi-layer system.
