We report the magnetic excitation spectrum as measured by inelastic neutron scattering for a polycrystalline sample of Sr3CuPtO6. Modeling the data by the 2+4 spinon contributions to the dynamical susceptibility within the chains, and with interchain coupling treated in the random phase approximation, accounts for the major features of the powder-averaged structure factor. The magnetic excitations broaden considerably as temperature is raised, persisting up to above 100 K and displaying a broad transition as previously seen in the susceptibility data. No spin gap is observed in the dispersive spin excitations at low momentum transfer, which is consistent with the gapless spinon continuum expected from the coordinate Bethe ansatz. However, the temperature dependence of the excitation spectrum gives evidence of some very weak interchain coupling.
@article{arxiv.1709.04100,
title = {Magnetic excitations of the Cu$^{2+}$ quantum spin chain in Sr$_3$CuPtO$_6$},
author = {J. C. Leiner and Joosung Oh and A. I. Kolesnikov and M. B. Stone and Manh Duc Le and E. P. Kenny and B. J. Powell and M. Mourigal and E. E. Gordon and M. -H. Whangbo and J. -W. Kim and S. -W. Cheong and Je-Geun Park},
journal= {arXiv preprint arXiv:1709.04100},
year = {2018}
}