Wang, MengValdivia, P.Yi, MingChen, J.X.Zhang, W.L.Ewings, R.A.Perring, T.G.Zhao, YangHarriger, L.W.Lynn, J.W.Bourret-Courchesne, E.Dai, PengchengLee, D.H.Yao, D. X.Birgeneau, R.J.2018-12-122018-12-122015Wang, Meng, Valdivia, P., Yi, Ming, et al.. "Spin waves and spatially anisotropic exchange interactions in the $S=2$ stripe antiferromagnet ${\mathrm{Rb}}_{0.8}{\mathrm{Fe}}_{1.5}{\mathrm{S}}_{2}$." <i>Physical Review B,</i> 92, no. 4 (2015) American Physical Society: https://doi.org/10.1103/PhysRevB.92.041109.https://hdl.handle.net/1911/103839An inelastic neutron scattering study of the spin waves corresponding to the stripe antiferromagnetic order in insulating Rb0.8Fe1.5S2 throughout the Brillouin zone is reported. The spin wave spectra are well described by a Heisenberg Hamiltonian with anisotropic in-plane exchange interactions. Integrating the ordered moment and the spin fluctuations results in a total moment squared of 27.6±4.2μ2B/Fe, consistent with S≈2. Unlike XFe2As2 (X=Ca, Sr, and Ba), where the itinerant electrons have a significant contribution, our data suggest that this stripe antiferromagnetically ordered phase in Rb0.8Fe1.5S2 is a Mott-like insulator with fully localized 3d electrons and a high-spin ground state configuration. Nevertheless, the anisotropic exchange couplings appear to be universal in the stripe phase of Fe pnictides and chalcogenides.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articlehttps://doi.org/10.1103/PhysRevB.92.041109