Polarized Neutron Studies for Cr Excitations

Abstract

The spin fluctuation mode of magnetic excitations in the spin densitywave (SDW) state of metallic chromium (Cr) was analyzed by means ofpolarization analysis of neutron scattering. Commensurate scatteringcentered at the antiferromagnetic superlattice position ofπ/a(1, 0, 0) is dominated by the longitudinal mode both below andabove the threshold energy of 8 meV with a different ratio againstthe transverse mode. On the other hand, magnetic excitationswith the wave vector of the static SDW were confirmed to be mostlylongitudinally polarized below 8 meV, but the scattering mode abovethis threshold energy was nearly isotropic.