Ferromagnetism of Nanosized Bilayer on Square Lattice Within Ising Model: Static and Dynamic Aspects with Size Effects Using Pair Approximation

In this study, the pair approximation in the Kikuchi version is applied to study ferromagnetism of a nanosized bilayer system on a square lattice using the Ising model. Each layer is divided into the core, core-surface and surface parts as introduced for the monolayers by Ozum et al. (2015). Temperature, magnetic field and interlayer exchange energy variations of the long- and short-range order parameters are investigated. Some second-order phase transitions between ferromagnetic and paramagnetic phases with size effects are observed. By using the path probability method, the flow of the system towards some stable equilibrium states in the ferromagnetic phase is obtained via relaxation curves and flow diagrams. The results of the numerical calculations are in a fairly good agreement with the available theoretical works of other authors.