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Neutron-Scattering Measurements of Spin Excitations in LaFeAsO and Ba(Fe0.953Co0.047)(2)As-2: Evidence for a Sharp Enhancement of Spin Fluctuations by Nematic Order

TitleNeutron-Scattering Measurements of Spin Excitations in LaFeAsO and Ba(Fe0.953Co0.047)(2)As-2: Evidence for a Sharp Enhancement of Spin Fluctuations by Nematic Order
Publication TypeJournal Article
Year of Publication2015
AuthorsZhang, Q, Fernandes, RM, Lamsal, J, Yan, JQ, Chi, SX, Tucker, GS, Pratt, DK, Lynn, JW, McCallum, RW, Canfield, PC, Lograsso, TA, Goldman, AI, Vaknin, D, McQueeney, RJ
JournalPhysical Review Letters
Volume114
Pagination057001
Date Published02
Type of ArticleArticle
ISBN Number0031-9007
Accession NumberWOS:000349249500017
Keywordsanisotropy, bafe2as2, detwinned ba(fe1-xcox)(2)as-2, high-temperature superconductivity, iron arsenide superconductor, pnictides, state, transition
Abstract

Inelastic neutron scattering is employed to investigate the impact of electronic nematic order on the magnetic spectra of LaFeAsO and Ba(Fe0.953Co0.047)(2)As-2. These materials are ideal to study the paramagnetic-nematic state, since the nematic order, signaled by the tetragonal-to-orthorhombic transition at T-S, sets in well above the stripe antiferromagnetic ordering at T-N. We find that the temperature-dependent dynamic susceptibility displays an anomaly at T-S followed by a sharp enhancement in the spin-spin correlation length, revealing a strong feedback effect of nematic order on the low-energy magnetic spectrum. Our findings can be consistently described by a model that attributes the structural or nematic transition to magnetic fluctuations, and unveils the key role played by nematic order in promoting the long-range stripe antiferromagnetic order in iron pnictides.

DOI10.1103/PhysRevLett.114.057001
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