title: Universality aspects of the d = 3 random-bond Blume-Capel model.
abstract: The effects of bond randomness on the universality aspects of the simple cubic lattice ferromagnetic Blume-Capel model are discussed. The system is studied numerically in both its first- and second-order phase transition regimes by a comprehensive finite-size scaling analysis. We find that our data for the second-order phase transition, emerging under random bonds from the second-order regime of the pure model, are compatible with the universality class of the 3d random Ising model. Furthermore, we find evidence that the second-order transition emerging under bond randomness from the first-order regime of the pure model belongs to a new and distinctive universality class. The first finding reinforces the scenario of a single universality class for the 3d Ising model with the three well-known types of quenched uncorrelated disorder (bond randomness, site and bond dilution). The second amounts to a strong violation of the universality principle of critical phenomena. For this case of the ex-first-order 3d Blume-Capel model, we find sharp differences from the critical behaviors, emerging under randomness, in the cases of the ex-first-order transitions of the corresponding weak and strong first-order transitions in the 3d three-state and four-state Potts models.
authors.affiliation: Department of Physics, Section of Solid State Physics, University of Athens, Panepistimiopolis, GR 15784 Zografos, Athens, Greece.
authors.forename: A
authors.initials: A
authors.lastname: Malakis
authors.forename: A Nihat
authors.initials: AN
authors.lastname: Berker
authors.forename: N G
authors.initials: NG
authors.lastname: Fytas
authors.forename: T
authors.initials: T
authors.lastname: Papakonstantinou
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D060526:Magnetic Fields; D008956:Models, Chemical; D015233:Models, Statistical