Crystal Chirality and Helicity of the Helical Spin Density Wave in MnSi. II. Polarized Neutron Diffraction

Abstract

Recent theoretical and experimental studies have shown the single handed helicity of the helical spin density wave in MnSi. In order to determine unambiguously the sense of the helicity we have carried out detailed experiments using pulsed polarized neutrons. Combining the result with that of the experiment on the crystal chirality, we have determined the left-handed or anticlockwise helicity for the left-handed chirality of the crystal symmetry. This leads to the positive sign of the antisymmetric exchange interaction in the left-handed chirality.