Monte Carlo Simulations of Ultrathin Magnetic Dots
  In this work we study the thermodynamic properties of ultrathin ferromagnetic dots using Monte Carlo simulations. We investigate the vortex density as a function of the temperature and the vortex structure in monolayer dots with perpendicular anisotropy and long-range dipole interaction. The interplay between these two terms in the hamiltonian leads to an interesting behavior of the thermodynamic quantities as well as the vortex density. 
M. Rapini, R. A. Dias, D. P. Landau, B. V. Costa