Frustração magnética em um modelo de ising triangular com anisotropia rotacional

• Autor(a) principal: Nascimento, Ricardo Mayckon Lopes
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/001300000bvmc
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/10735
• topic: Sistemas magnéticos frustrados; Simulações entrópicas; Transições de fase; Magnetic frustrated systems; Entropic simulations; Phase transitions; CIENCIAS EXATAS E DA TERRA::FISICA

In this work, we present a new model for the study of frustrated magnetic systems proposed for a triangular lattice equipped with Ising type spins that takes into account not only the interaction between the spins but also the interaction due to the symmetry of a given substrate that corresponds to a host lattice of the magnetic system. This last interaction is related to a phenomenological parameter that is responsible for controlling the intensity of this interaction and that is proportional to a function representative of the symmetry of the host material in question. The interest behind this study seeks to characterize the influence of this interaction on the behavior of the spins through the evaluation of their main thermodynamic properties associated with a phase transition that imply a new way of modeling these systems pointing to a complementary view of what can promote frustration in magnetic systems in general. For the development of this research, we adopted entropic sampling simulations based on the Wang-Landau method, where a random walk in the energy space is performed, allowing to estimate the density of states g(E) while the energy distribution is generated in the histogram. Through this methodology, we calculated some thermodynamic properties of interest and managed to represent a phase diagram that illustrates the various forms that the system takes in function of a control parameter that is responsible for adjusting the different magnetic phases of the model. We also adopted the finite-size scale theory that allowed us to estimate the critical exponents corresponding to a certain class of universality that the system may belong to. As a result of this, we were able to establish the proper conclusions regarding the dynamics of the system and we became able to formulate the possible developments resulting from this work.