Reinvestigation of magnetic excitations in the spin density wave of chromium

Low-energy magnetic excitations of chromium have been reinvestigated with a single-(formula presented) crystal using neutron scattering techniques. In the transverse spin-density-wave phase a well-defined magnetic excitation is found around (formula presented) with a weak dispersion perpendicular to the wave vector of the incommensurate structure. The magnetic excitation has an energy gap of (formula presented) at (formula presented) which exactly corresponds to the Fincher excitation previously studied only along the incommensurate wave vector.