Magnetic phases of the quasi-two-dimensional compounds FexCo1 - xTa2O6

E. G. Santos (1) , S. R. de Oliveira Neto (2) , E. J. Kinast (3) , J. B. M. da Cunha (1) , Olivier Isnard (4) , M. A. Gusmao (1)

1 UFRGS - Universidade Federal do Rio Grande do Sul [Porto Alegre]
2 UFS - UFS
3 UERGS - UERGS
4 NEEL - MRS - Matériaux, Rayonnements, Structure

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.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

E. G. Santos, S. R. de Oliveira Neto, E. J. Kinast, J. B. M. da Cunha, Olivier Isnard, et al.. Magnetic phases of the quasi-two-dimensional compounds FexCo1 - xTa2O6. Journal of Physics: Condensed Matter, 2010, 22, pp.6004. ⟨10.1088/0953-8984/22/49/496004⟩. ⟨hal-00978118⟩