title: Critical behavior of the spin-1 and spin-3/2 Baxter-Wu model in a crystal field.
abstract: The phase diagram and the critical behavior of the spin-1 and the spin-3/2 two-dimensional Baxter-Wu model in a crystal field are studied by conventional finite-size scaling and conformal invariance theory. The phase diagram of this model, for the spin-1 case, is qualitatively the same as those of the diluted 4-states Potts model and the spin-1 Blume-Capel model. However, for the present case, instead of a tricritical point one has a pentacritical point for a finite value of the crystal field, in disagreement with previous work based on finite-size calculations. On the other hand, for the spin-3/2 case, the phase diagram is much richer and can present, besides a pentacritical point, an additional multicritical end point. Our results also support that the universality class of the critical behavior of the spin-1 and spin-3/2 Baxter-Wu model in a crystal field is the same as the pure Baxter-Wu model, even at the multicritical points.
authors.affiliation: Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Caixa Postal 702, 30123-970 Belo Horizonte, Minas Gerais, Brazil.|Universidade Federal de Uberlândia, Campus Patos de Minas, Av. Getúlio Vargas 230, 38700-103 Patos de Minas, Minas Gerais, Brazil.
authors.forename: D A
authors.initials: DA
authors.lastname: Dias
authors.affiliation: Instituto de Física, Universidade Federal de Uberlândia, Caixa Postal 593, 38400-902 Uberlândia, Minas Gerais, Brazil.
authors.forename: J C
authors.initials: JC
authors.lastname: Xavier
authors.affiliation: Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Caixa Postal 702, 30123-970 Belo Horizonte, Minas Gerais, Brazil.|Universidade Federal da Paraíba, Centro de Ciências Exatas e da Natureza, Campus I, Departamento de Física, CCEN Cidade Universitária, 58051-970 João Pessoa, Paraíba, Brazil.|Center for Simulational Physics, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Plascak