Abstract
We develop the technique to study the spin-wave dynamics of the full-polarized state of the Dzyaloshinskii-Moriya helimagnets by polarized small-angle neutron scattering. We have experimentally proven that the spin-waves dispersion in this state has the anisotropic form. We show that the neutron scattering image displays a circle with a certain radius which is centered at the momentum transfer corresponding to the helix wave vector in helimagnetic phase , which is oriented along the applied magnetic field . The radius of this circle is directly related to the spin-wave stiffness of this system. This scattering depends on the neutron polarization showing the one-handed nature of the spin waves in Dzyaloshinskii-Moriya helimagnets in the full-polarized phase. We show that the spin-wave stiffness for MnSi helimagnet decreased twice as the temperature increases from zero to the critical temperature .
- Received 3 August 2015
- Revised 1 December 2015
DOI:https://doi.org/10.1103/PhysRevB.92.220415
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