Langevin simulations of a model for ultrathin magnetic films

Abstract

We show results from simulations of the Langevin dynamics of a two-dimensional scalar model with competing interactions for ultrathin magnetic films. We find a phase transition from a high temperature disordered phase to a low temperature phase with both positional and orientational orders. Both kinds of order emerge at the same temperature, probably due to the isotropy of the model Hamiltonian. In the low temperature phase orientational correlations show long range order while positional correlations show only quasi-long-range order in a wide temperature range. The orientational correlation length and the associated susceptibility seem to diverge with power laws at the transition. While at zero temperature the system exhibits stripe long range order, as temperature grows we observe the proliferation of different kinds of topological defects that ultimately drive the system to the disordered phase. The magnetic structures observed are similar to experimental results on ultrathin ferromagnetic films.

extended introduction, added references

References in corpus (5)

• Hysteresis loops of magnetic thin films with perpendicular anisotropy
• Computer simulations of two-dimensional melting with dipole-dipole interactions
• Ising nematic phase in ultra-thin magnetic films: a Monte Carlo study
• Competing Interactions, the Renormalization Group and the Isotropic-Nematic Phase Transition
• Langevin dynamics of fluctuation induced first order phase transitions: self consistent Hartree Approximation

Cited by in corpus (20)

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• Nature of Long-Range Order in Stripe-Forming Systems with Long-Range Repulsive Interactions
• Magnetic domain wall creep and depinning: a scalar field model approach
• Nematic phase in the J${}_1$-J${}_2$ square lattice Ising model in an external field
• H-T phase diagram of the bi-dimensional Ising model with exchange and dipolar interactions
• The nematic phase in stripe forming systems within the self consistent screening approximation
• Prethermal nematic order and staircase heating in a driven frustrated Ising magnet with dipolar interactions
• T=0 phase diagram and nature of domains in ultrathin ferromagnetic films with perpendicular anisotropy
• On the mechanism behind the inverse melting in systems with competing interactions
• Microscopic approach to orientational order of domain walls
• Melting of the two-dimensional solid phase in the Gaussian-core model
• Pair correlations and structure factor of the $J_1$-$J_2$ square lattice Ising model in an external field within the Cluster Variation Method
• Finite temperature phase diagram of ultrathin magnetic films without external fields
• Degradation of domains with sequential field application
• Tuning Ginzburg-Landau theory to quantitatively study thin ferromagnetic materials
• Topological phase diagrams of the frustrated Ising ferromagnet
• Dynamics of systems with isotropic competing interactions in an external field: a Langevin approach
• Inverse transition in the dipolar frustrated Ising ferromagnet: the role of domain walls
• Non-Arrhenius relaxation of the Heisenberg model with dipolar and anisotropic interactions
• The frustrated spherical model: an alternative to Ginzburg-Landau Hamiltonians with competing interactions