Simulations of disordered magnetic materials

Sammanfattning

In this thesis, we aim to study three different magnetic materials using the classical Heisenbergmodel in 3D and the Metropolis-Hastings algorithm. The materials studied were; ferromagnets,antiferromagnets, and spin glass. The different materials were studied using numerical Monte Carlosimulations, where convergence behaviour, order parameters, and statistical errors were analysed.After initial studies of the materials were performed, a study on how the critical temperaturedepended on standard deviation when the coupling constant Jij ∼ N (1, σ2) with σ = [0, 3] wasperformed. The results show that the critical temperature of the system decreases when σ wasincreased from 0 to 1. This result is consistent with Izardar and Ederers recent findings [1].When the standard deviation was further increased above 1, our model could not provide statis-tically reliable results, thus further numerical studies and research into standard deviations in thisdomain is required