Chirality in Dy/Y multilayer

Chirality plays a crucial role in a wide variety of disciplines from biology to chemistry and physics. However, in the field of magnetism it did not attract a lot of attention until recently, when it was demonstrated for the first time that a single layer of manganese on tungsten orders of a specific chirality. It was interpreted being caused by the Dzyaloshinskii-Moriya (DM) interaction which arises from spin-orbit interactions of electrons due to the breaking of the inversion symmetry at the interface. Here, we present studies using polarized neutron scattering on Dy/Y multilayer structures demonstrating that the magnetic system possess a coherent spin helix with a preferable chirality induced by the magnetic field. The average chirality, being proportional to the difference in the left- and right-handed helix population numbers, is measured as a polarization-dependent asymmetric part of the magnetic neutron scattering. The magnetic field applied in the plane of the sample upon cooling below TN is able to repopulate the otherwise equal population numbers for the left- and right-handed helixes. The experimental results strongly indicate that chirality observed here for the first time in a multilayer system is a more general phenomenon and may play an important role in future spintronic devices.