Neutron scattering from a coordination polymer quantum paramagnet

Abstract
Inelastic neutron scattering measurements are reported for a powder sample of the spin-1/2 quantum paramagnet Cu(quinoxaline)Br2. Magnetic neutron scattering is identified above an energy gap of 1.9 meV. Analysis of the sharp spectral maximum at the onset indicates that the material is magnetically quasi-one-dimensional. Consideration of the wave vector dependence of the scattering and polymeric structure further identifies the material as a two-legged spin-1/2 ladder. Detailed comparisons of the data to various models of magnetism in this material based on the single-mode approximation and the continuous unitary transformation are presented. The latter theory provides an excellent account of the data with leg exchange J∥=2.0 meV and rung exchange J⊥=3.3 meV.
Description
Keywords
Cu(Quinoxaline)Br2, coordination polymer quantum paramagnet, wave vector, quasione-dimensional magnetic material, spin dynamics, polymers, two-legged spin-1/2 ladder, paramagnetic materials, neutron diffraction, exchange interactions (electron), energy gap, single mode approximation, leg exchange, rung exchange
Citation
Physical Review B (Condensed Matter and Materials Physics) 1 Sept. 2006, vol.74, no.9, pp. 94434-1-9