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Similar zone-center gaps in the low-energy spin-wave spectra of Na1-delta FeAs and BaFe2As2

Title
Similar zone-center gaps in the low-energy spin-wave spectra of Na1-delta FeAs and BaFe2As2
Authors
Park, JT[Park, J. T.]Friemel, G[Friemel, G.]Loew, T[Loew, T.]Hinkov, V[Hinkov, V.]Li, Y[Li, Yuan]Min, BH[Min, B. H.]Sun, DL[Sun, D. L.]Ivanov, A[Ivanov, A.]Piovano, A[Piovano, A.]Lin, CT[Lin, C. T.]Keimer, B[Keimer, B.]Kwon, YS[Kwon, Y. S.]Inosov, DS[Inosov, D. S.]
DGIST Authors
Min, BH[Min, B. H.]; Kwon, YS[Kwon, Y. S.]
Issue Date
2012-07-27
Citation
Physical Review B: Condensed Matter and Materials Physics, 86(2)
Type
Article
Article Type
Article
ISSN
2469-9950
Abstract
We report results of inelastic-neutron-scattering measurements of low-energy spin-wave excitations in two structurally distinct families of iron-pnictide parent compounds: Na 1-δFeAs and BaFe 2As 2. Despite their very different values of the ordered magnetic moment and Néel temperatures, T N, in the antiferromagnetic state both compounds exhibit similar spin gaps of the order of 10 meV at the magnetic Brillouin-zone center. The gap opens sharply below T N, with no signatures of a precursor gap at temperatures between the orthorhombic and magnetic phase transitions in Na 1-δFeAs. We also find a relatively weak dispersion of the spin-wave gap in BaFe 2As 2 along the out-of-plane momentum component, q z. At the magnetic zone boundary (q z=0), spin excitations in the ordered state persist down to ∼20 meV, which implies a much smaller value of the effective out-of-plane exchange interaction, J c, as compared to previous estimates based on fitting the high-energy spin-wave dispersion to a Heisenberg-type model. © 2012 American Physical Society.
URI
http://hdl.handle.net/20.500.11750/3352
DOI
10.1103/PhysRevB.86.024437
Publisher
American Physical Society
Files:
There are no files associated with this item.
Collection:
Emerging Materials ScienceQuantum Functional Materials Laboratory1. Journal Articles


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