title: Magnetic phases of the quasi-two-dimensional compounds FexCo1 - xTa2O6.
abstract: We report new results on the magnetic properties of the FexCo1 - xTa2O6 series of compounds. Essentially using neutron-diffraction and magnetic measurements we study, in more detail, the low-x limit of the temperature versus x phase diagram, where a new bicritical point is observed. The complete phase diagram shows three different magnetic phases at low temperature, for a high, intermediate and very low iron content. These phases consist of distinct antiferromagnetic orderings, characterized by different pairs of propagation vectors. We obtain information about the intraplane exchange interactions by fitting a high-temperature series of the magnetic susceptibility. Here we improve on a previously employed model, showing that two non-equivalent next-nearest-neighbor interactions must be taken into account in order to allow for in-plane magnetic orderings that are consistent with the neutron-diffraction results.
authors.affiliation: Instituto de Física, Universidade Federal do Rio Grande do Sul, CP 15051, 91501-970 Porto Alegre, Brazil.
authors.forename: E G
authors.initials: EG
authors.lastname: Santos
authors.forename: S R
authors.initials: SR
authors.lastname: de Oliveira Neto
authors.forename: E J
authors.initials: EJ
authors.lastname: Kinast
authors.forename: J B M
authors.initials: JB
authors.lastname: da Cunha
authors.forename: O
authors.initials: O
authors.lastname: Isnard
authors.forename: M A
authors.initials: MA
authors.lastname: Gusmão