Publication Type
Journal
Journal Name
Physical Review Letters
Publication Date
Page Number
227205
Volume
101
Issue
22
Abstract
Inelastic neutron scattering measurements of the magnetic excitations in CaFe2As2
indicate that the spin wave velocity in the Fe layers is exceptionally large and similar in
magnitude to the cuprates. However, the spin wave velocity perpendicular to the layers is
at least half as large that in the layer, so that the magnetism is more appropriately categorized as anisotropic three-dimensional, in contrast to the two-dimensional cuprates. Exchange constants derived from band structure calculations predict spin wave velocities that are consistent with the experimental data.
