12th Joint MMM/Intermag Conference
The phonon dispersion was measured at room temperature (above the Néel temperature TN) along (0,0,L) in the tetragonal phase of LaFeAsO using inelastic x-ray scattering. Magnetostructural effects are well documented in the AFe2As2-based (A = Ca, Sr, Ba, Eu) systems. Only recently have single crystals of LaFeAsO become available. The experimentally observed splitting between two A1g phonon modes at 22 and 26 meV is only reproduced in spin-polarized calculations. Magnetostructural effects similar to those observed in the AFe2As2 materials are confirmed to be present in LaFeAsO. This is discussed in terms of the strong antiferromagnetic correlations that are known to persist above TN and into the tetragonal phase.
American Institute of Physics
Hahn, Steven E.; Tucker, Gregory S.; Yan, J.-Q.; Said, A. H.; Leu, B. M.; McCallum, R. William; Alp, E. E.; Lograsso, Thomas A.; McQueeney, Robert J.; and Harmon, Bruce N., "Magnetism dependent phonon anomaly in LaFeAsO observed via inelastic x-ray scattering" (2013). Ames Laboratory Conference Papers, Posters, and Presentations. 4.