Effect of Disorder on Phase Transitions in Antidote Lattice Thin Films: Computer Simulations

Computer modeling of a thin ferromagnetic film with an antidote lattice is carried out using the Monte Carlo method. The model considers random displacements in the location of pores. The Ising model is used to describe the magnetic properties of the system. The Metropolis's algorithm forms the thermodynamic states of the system. The finite-dimensional scaling theory is used to calculate the Curie temperature of the system and critical exponents. The Curie temperature is calculated for various ratio for the size of a pore and the period for a lattice of antidotes. A computer experiment showed a logarithmic dependence of the phase transition temperature on the pore area on the film surface. Critical exponents are calculated for different pore sizes. Two types of critical behavior can be observed in the system as the pore area increases. Each class of critical behavior has its own set of critical exponents. The first universality class coincides with the universality class for a continuous thin film. There is a critical pore size that creates a new class of universality for critical behavior. Small deviations in the arrangement of pores from the nodes of the square lattice do not change the Curie temperature and critical exponents. The critical parameter is the relative pore area.