Abstract
We present powder inelastic neutron scattering measurements of the dimerized antiferromagnet . The magnetic spectrum exhibits a spin gap of and a dispersive spectrum with a bandwidth of approximately . A comparison to coupled dimer models accurately describes the dispersion and scattering intensity and determines the exchange constants in . The wave vector dependent scattering intensity confirms the proposed dimer bond. Temperature dependent measurements of the magnetic excitations indicate the presence of both singlet-triplet and thermally activated triplet-quintet excitations.
1 More- Received 15 January 2008
DOI:https://doi.org/10.1103/PhysRevB.77.134406
©2008 American Physical Society