T=0 phase diagram and nature of domains in ultrathin ferromagnetic films with perpendicular anisotropy

Abstract

We present the complete zero temperature phase diagram of a model for ultrathin films with perpendicular anisotropy. The whole parameter space of relevant coupling constants is studied in first order anisotropy approximation. Because the ground state is known to be formed by perpendicular stripes separated by Bloch walls, a standard variational approach is used, complemented with specially designed Monte Carlo simulations. We can distinguish four regimes according to the different nature of striped domains: a high anisotropy Ising regime with sharp domain walls, a saturated stripe regime with thicker walls inside which an in-plane component of the magnetization develops, a narrow canted-like regime, characterized by a sinusoidal variation of both the in-plane and the out of plane magnetization components, which upon further decrease of the anisotropy leads to an in-plane ferromagnetic state via a spin reorientation transition (SRT). The nature of domains and walls are described in some detail together with the variation of domain width with anisotropy, for any value of exchange and dipolar interactions. Our results, although strictly valid at $T=0$, can be valuable for interpreting data on the evolution of domain width at finite temperature, a still largely open problem.

7 pages, 4 figures. Short version of arXiv:0907.5153, accepted for publication in JMMM (2010)

References in corpus (4)

• Phase diagram of an Ising model for ultrathin magnetic films
• The Spin Reorientation Transition and Phase Diagram of Ultrathin Ferromagnetic Films
• Stripe width and non-local domain walls in the two-dimensional Dipolar Frustrated Ising Ferromagnet
• Langevin simulations of a model for ultrathin magnetic films

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• Domain-wall free energy in Heisenberg ferromagnets
• Topological phase diagrams of the frustrated Ising ferromagnet
• Inverse transition in the dipolar frustrated Ising ferromagnet: the role of domain walls
• Phase diagram of the dipolar Ising ferromagnet on a kagome lattice
• Anisotropy-based mechanism for zigzag striped patterns in magnetic thin films
• Non-Arrhenius relaxation of the Heisenberg model with dipolar and anisotropic interactions