'Theory for the enhanced induced magnetization in coupled magnetic trilayers in the presence of spin fluctuations'

Abstract

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 $T_{C,\mathrm{Ni}}$ 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.

4 pages, 3 figures

References in corpus (1)

• 1/N expansion for two-dimensional quantum ferromagnets

Cited by in corpus (4)

• Quantum Monte Carlo simulation of thin magnetic films
• In-plane dipole coupling anisotropy of a square ferromagnetic Heisenberg monolayer
• Comment on "Magnetic phase transition in Co/Cu/Ni/Cu(100) and Co/Fe/Ni/Cu(100)"
• Phase transitions in random magnetic bilayer