%0 Journal Article
%T 'Theory for the enhanced induced magnetization in coupled magnetic trilayers in the presence of spin fluctuations'
%A P. J. Jensen
%A K. H. Bennemann
%A P. Poulopoulos
%A M. Farle
%A F. Wilhelm
%A K. Baberschke
%J Physics
%D 1999
%I arXiv
%R 10.1103/PhysRevB.60.R14994
%X Motivated by recent experiments, the effect of the interlayer exchange interaction $J_{inter}$ on the magnetic properties of coupled Co/Cu/Ni trilayers is studied theoretically. Here the Ni film has a lower Curie temperature $T_{C,\rm Ni}$ than the Co film in case of decoupled layers. We show that by taking into account magnetic fluctuations the interlayer coupling induces a strong magnetization for $T\gtsim T_{C,\rm Ni}$ in the Ni film. For an increasing $J_{inter}$ the resonance-like peak of the longitudinal Ni susceptibility is shifted to larger temperatures, whereas its maximum value decreases strongly. A decreasing Ni film thickness enhances the induced Ni magnetization for $T\gtsim T_{C,\rm Ni}$. The measurements cannot be explained properly by a mean field estimate, which yields a ten times smaller effect. Thus, the observed magnetic properties indicate the strong effect of 2D magnetic fluctuations in these layered magnetic systems. The calculations are performed with the help of a Heisenberg Hamiltonian and a Green's function approach.
%U http://arxiv.org/abs/cond-mat/9910149v1