Dimensionality crossover in critical behaviour of ultrathin ferromagnetic films

We propose the model which takes account of magnetocrystalline anisotropy effects in thin magnetic films. The dimensionality crossover from two-dimensional monolayer to three-dimensional system in multilayer magnetic films is studied using a Monte Carlo technique. Finite-size scaling is applied for the determination of the critical characteristics as a function of film thickness. The transition to intermediate planar phase is discussed. •We make Monte Carlo simulations in a anisotropy Heisenberg films.•Anisotropy effects lead to dimensionality crossover in Heisenberg films.•The transition to intermediate XY-like phase for 14–19 ML was discovered.•The critical exponents agree with experiments for Ni and Co films.