Phase transitions and critical phenomena in the two-dimensional Ising model with dipole interactions: A short-time dynamics study

C. M. HOROWITZ; M. A. BAB; M. MAZZINI; M. L. RUBIO PUZZO; G. P. SARACCO

PHYSICAL REVIEW E - STATISTICAL PHYSICS, PLASMAS, FLUIDS AND RELATED INTERDISCIPLINARY TOPICS

APS

Año: 2015 vol. 92 p. 421271 - 421278

1063-651X

The ferromagnetic Ising model with antiferromagnetic dipole interactions is investigated by means of Monte Carlo simulations, focusing on the characterization of the phase transitions between the tetragonal liquid and stripe of width h phases. The dynamic evolution of the physical observables is analyzed within the short-time regime for 0.5leq delta leq 1.3, where delta is the ratio between the short-range exchange and the long-range dipole interaction constants. The obtained results for the interval 0.5leq delta leq 1.2 indicate that the phase transition line between the h=1-stripe and tetragonal liquid phases is continous. This finding contributes to clarify the controversy about the order of this transition. This controversy arises from the difficulties introduced in the simulations due to the presence of long-range dipole interactions, such as an important increase in the simulation times that limits the system size used, strong finite size effects, as well as to the existence of multiple metastable states at low temperatures. The study of the short-time dynamics of the model allows us to avoid these hindrances. Moreover, due to the fact that the finite-size effects do not significantly affect the power-law behavior exhibited in the observables within the short-time regime, the results could be attributed to those corresponding to the thermodynamic limit. As a consequence of this, a careful characterization of the critical behavior for the whole transition line is performed by giving the complete set of critical exponents.