title: Potential signature of a Kosterlitz-Thouless transition in BaNi2V2O8.
abstract: ESR measurements are reported for the quasi-two-dimensional honeycomb antiferromagnet BaNi2V2O8. Planar anisotropic properties are confirmed by angular dependent investigations of resonance field and linewidth. The divergence of the temperature-dependent linewidth on approaching T(N) from above is described in terms of the Kosterlitz-Thouless transition, the critical behavior close to long-range magnetic order, and the 2D Heisenberg antiferromagnet. We provide arguments that the Kosterlitz-Thouless scenario is compatible with the observed critical exponent and suggest BaNi2V2O8 is a weakly anisotropic 2D Heisenberg antiferromagnet.
authors.affiliation: Experimentalphysik V, Elektronische Korrelationen und Magnetismus, Institut für Physik, Universität Augsburg, D-86135 Augsburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Heinrich
authors.forename: H-A
authors.initials: HA
authors.lastname: Krug von Nidda
authors.forename: A
authors.initials: A
authors.lastname: Loidl
authors.forename: N
authors.initials: N
authors.lastname: Rogado
authors.forename: R J
authors.initials: RJ
authors.lastname: Cava