Regular Article - Statistical and Nonlinear Physics
Phase diagrams and magnetization curves of the mixed Ashkin–Teller model including metastable and unstable states
Departamento de Ciências Naturais, Universidade Federal de São João del-Rei, C.P. 110, 36301-160, São João del-Rei, MG, Brazil
2 Departamento de Matemática, Universidade Federal de São João del-Rei, C.P. 110, 36301-160, São João del-Rei, MG, Brazil
Accepted: 21 June 2021
Published online: 1 July 2021
We investigate the magnetic properties of a mixed Ashkin–Teller model (spin-1/2 and spin-1) in a square lattice, under the effect of a crystal field, using the mean-field theory. Phase diagrams, magnetizations and free energy curves are presented. Besides the stable states of the order parameters, we also obtain the metastable and unstable states, which are shown in the phase diagrams and magnetization curves. The classification of the stable, metastable and unstable states is made by comparing their free-energy values.
© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2021