Spin Waves and Spatially Anisotropic Exchange Interactions in the S = 2 Stripe Antiferromagnet Rb0.8Fe1.5S2

Published

July 13, 2015

Author(s)

Meng Wang, P. Valdivia, Ming Yi, J. X. Chen, W. L. Zhang, R. A. Ewings, T. G. Perring, Yang Zhao, Leland Harriger, Jeffrey W. Lynn, E. Bourret-Courchesne, Pengcheng Dai, D. H. Lee, D. X. Yao, R. J. Birgeneau

Abstract

An inelastic neutron scattering study of the spin waves corresponding to the stripe antiferromagnetic order in insulating Rb_0.8Fe_1.5S₂ 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 26 ±3υ²_B/Fe, consistent with S approximately equal} 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 Rb_0.8Fe_1.5S₂ 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.

Citation

Physical Review B

Volume

92

Issue

4

Pub Type

Journals

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Keywords

Iron superconductors, Spin Waves, Inelastic neutron scattering, anisotropic exchange, Heisenberg Hamiltonian

Citation

Wang, M. , Valdivia, P. , Yi, M. , Chen, J. , Zhang, W. , Ewings, R. , Perring, T. , Zhao, Y. , Harriger, L. , Lynn, J. , Bourret-Courchesne, E. , Dai, P. , Lee, D. , Yao, D. and Birgeneau, R. (2015), Spin Waves and Spatially Anisotropic Exchange Interactions in the S = 2 Stripe Antiferromagnet Rb_0.8Fe_1.5S₂, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=918520 (Accessed October 11, 2025)