Neutron scattering signature of the Dzyaloshinskii-Moriya interaction in nanoparticles

The antisymmetric Dzyaloshinkii-Moriya interaction (DMI) arises in systems with broken inversion symmetry and strong spin-orbit coupling. In conjunction with the isotropic and symmetric exchange interaction, magnetic anisotropy, the dipolar interaction, and an externally applied magnetic field, the DMI supports and stabilizes the formation of various kinds of complex mesoscale magnetization configurations, such as helices, spin spirals, skyrmions, or hopfions. A question of importance in this context addresses the neutron scattering signature of the DMI, in particular in nanoparticle assemblies, where the related magnetic scattering signal is diffuse in character and not of the single-crystal diffraction-peak type, as it is, e.g., seen in the B20 compounds. Using micromagnetic simulations we study the effect of the DMI in spherical FeGe nanoparticles on the randomly averaged magnetic neutron scattering observables, more specifically on the spin-flip small-angle neutron scattering cross section, the related chiral function, and the pair-distance distribution function. Within the studied parameter space for the particle size (60nm≤