Modelo de Ising de spins mistos com desordem temperada em diferentes tipos de redes e anisotropias

• Ano de defesa: 2023
• Autor(a) principal: Santana, Elpidio Sousa
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Mato Grosso; Brasil; Instituto de Física (IF); UFMT CUC - Cuiabá; Programa de Pós-Graduação em Física
• Palavras-chave em Português: Modelo de Ising; Simulação de Monte Carlo; Anisotropias aleatórias; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA; Ising model; Monte Carlo simulation; Aleatory anisotropies
• Link de acesso: http://ri.ufmt.br/handle/1/5558

In this work, we have investigated the phase diagrams of the ferromagnetic binary alloys with quenched disorder and different single-ion anisotropies. We have employed Monte Carlo simulations in the mixed-spin Ising model on three different types of lattices: square, triangular, and honeycomb with the influence of anisotropies. These lattices are divided into two sublattices, with spins σ = 1/2 occupying sublattice A and distributed randomly following a distribution c, while sublattice B is composed of spins S = 1. The lattices have a ferromagnetic interaction (J > 0) between their nearest neighbor spins and exhibit a single-ion anisotropy D, which, in some cases, can also be random. The magnetic properties of the system were calculated, including magnetization (m), susceptibility (χ), energy (e), specific heat capacity (c), and Binder cumulant (U), for various lattice dimensions (L). We also have constructed the phase diagram of the model in the critical temperature (Tc) versus the anisotropy (D) plane and the critical temperature (Tc) versus the concentration (c) plane, as well as in the phase diagram. This diagram displays lines of first and second-order phase transitions for different anisotropy distributions.