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

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • J. T. Park - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)
  • G. Friemel - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)
  • T. Loew - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)
  • V. Hinkov - , University of British Columbia (Author)
  • Yuan Li - , Peking University (Author)
  • B. H. Min - , Daegu Gyeongbuk Institute of Science and Technology (Author)
  • D. L. Sun - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)
  • A. Ivanov - , ILL - Institut Laue-Langevin (Author)
  • A. Piovano - , ILL - Institut Laue-Langevin (Author)
  • C. T. Lin - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)
  • B. Keimer - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)
  • Y. S. Kwon - , Daegu Gyeongbuk Institute of Science and Technology (Author)
  • D. S. Inosov - , Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Author)

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: Na1-delta FeAs and BaFe2As2. Despite their very different values of the ordered magnetic moment and Neel 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 Na1-delta FeAs. We also find a relatively weak dispersion of the spin-wave gap in BaFe2As2 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 similar 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.

Details

Original languageEnglish
Article number024437
Number of pages6
JournalPhysical Review B
Volume86
Issue number2
Publication statusPublished - 27 Jul 2012
Peer-reviewedYes
Externally publishedYes

External IDs

Scopus 84864449287

Keywords

Keywords

  • HIGH-TEMPERATURE SUPERCONDUCTIVITY, LAYERED SUPERCONDUCTOR

Library keywords