title: Interplay between spin-glass clusters and geometrical frustration.
abstract: The presence of spin-glass (SG) order in highly geometrically frustrated systems is analyzed in a cluster SG model. The model considers infinite-range disordered interactions among cluster magnetic moments and the J(1)-J(2) model couplings between Ising spins of the same cluster. This model can introduce two sources of frustration: one coming from the disordered interactions and another coming from the J(1)-J(2) intracluster interactions (intrinsic frustration). The framework of one-step replica symmetry breaking is adopted to obtain a one-cluster problem that is exactly solved. As a main result we create phase diagrams of the temperature T versus intensity of the disorder J, where the paramagnetic-SG phase transition occurs at T(f) when T decreases for high-J values. For low-J values, the SG order is absent for antiferromagnetic clusters without intrinsic frustration. However, the SG order can be observed within the intracluster intrinsic frustration regime even for lower intensity of disorder. In particular, the results indicate that the presence of small clusters in geometrically frustrated antiferromagnetic systems can help stabilize the SG order within a weak disorder.
authors.affiliation: Departamento de Fisica, Universidade Federal de Santa Maria, 97105-900 Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: F M
authors.initials: FM
authors.lastname: Zimmer
authors.forename: C F
authors.initials: CF
authors.lastname: Silva
authors.forename: S G
authors.initials: SG
authors.lastname: Magalhaes
authors.affiliation: Université Grenoble Alpes, Institut Néel, F-38042 Grenoble, France and CNRS, Institut Néel, F-38042 Grenoble, France.
authors.forename: C
authors.initials: C
authors.lastname: Lacroix