title: Small-cluster renormalization group in Ising and Blume-Emery-Griffiths models with ferromagnetic, antiferromagnetic, and quenched disordered magnetic interactions.
abstract: The Ising and Blume-Emery-Griffiths (BEG) models' critical behavior is analyzed in two dimensions and three dimensions by means of a renormalization group scheme on small clusters made of a few lattice cells. Different kinds of cells are proposed for both ordered and disordered model cases. In particular, cells preserving a possible antiferromagnetic ordering under renormalization allow for the determination of the Néel critical point and its scaling indices. These also provide more reliable estimates of the Curie fixed point than those obtained using cells preserving only the ferromagnetic ordering. In all studied dimensions, the present procedure does not yield a strong-disorder critical point corresponding to the transition to the spin-glass phase. This limitation is thoroughly analyzed and motivated.
authors.affiliation: IPCF-CNR, UOS Roma Kerberos, P.le Aldo Moro 2, I-00185 Rome, Italy and Dipartimento di Fisica, Università "Sapienza", P.le Aldo Moro 2, I-00185 Rome, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Antenucci
authors.affiliation: Dipartimento di Fisica, Università "Sapienza", P.le Aldo Moro 2, I-00185 Rome, Italy and ISC-CNR, UOS Sapienza, P.le Aldo Moro 2, I-00185 Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Crisanti
authors.affiliation: IPCF-CNR, UOS Roma Kerberos, P.le Aldo Moro 2, I-00185 Rome, Italy and Dipartimento di Fisica, Università "Sapienza", P.le Aldo Moro 2, I-00185 Rome, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Leuzzi
mesh_terms: D060328:Magnetic Phenomena; D008962:Models, Theoretical; D016011:Normal Distribution