Critical behavior analysis of pure dipolar triangular lattice via equilibrium and nonequilibrium Monte Carlo simulations

Magnetic thin films and two-dimensional (2D) arrays of magnetic nanoparticles exhibit unique physical properties that make them valuable for a wide range of technological applications. In such systems, dipolar interactions play a crucial role in determining their physical behavior. However, due to the anisotropic and long-range nature of dipolar interactions, conventional Monte Carlo (MC) methods face challenges in investigating these systems near criticality. In this study, we examine the critical behavior of a triangular lattice of XY dipoles using the optimized Tomita MC algorithm tailored for dipolar interactions. We employ two independent computational approaches to estimate the critical temperature and exponents: equilibrium MC simulations with histogram reweighting and the nonequilibrium relaxation method. Notably, both approaches demonstrate that this XY dipolar system might be in a new universality class very close to the 2D Ising universality class.