Dzyaloshinski-Moriya Interactions and Berry Curvature in Magnetic Nanoparticles

ORAL

Abstract

Noncentrosymmetric crystals, such as B20-ordered MnSi, have long been known to exhibit spin spirals in the bulk and skyrmions with quantized topological charge in thin films. We have theoretically and experimentally investigated the skyrmions of magnetic nanoparticles produced by cluster deposition. Our research includes CoSi, which is nonmagnetic in the bulk but magnetically ordered in nanoparticle form. The size confinement imposed by the nanostructuring suppresses the formation of spin spirals and skyrmions but leads top the formation of curling-type spin structures with nonzero Berry curvature and nonzero contribution to the topological Hall effect (THE). Concerning the nanoparticle material, there is an important distinction between centrosymmetric materials and various types of materials without inversion symmetry, especially polar and chiral crystal structures. With respect to the spin states, the former corresponds to broken chirality, whereas the latter imply a violation of chiral symmetry. It is interesting to note that moderately strong Berry curvatures and unquantized THE contributions may also be caused in nanoparticles with inversion symmetry and due to magnetostatic interactions.

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Presenters

  • Ralph Skomski

    Nebraska Center for Materials and Nanoscience and Department of Physics and Astronomy,, University of Nebraska, Lincoln, Nebraska 68588-0299, USA, University of Nebraska - Lincoln

Authors

  • Ralph Skomski

    Nebraska Center for Materials and Nanoscience and Department of Physics and Astronomy,, University of Nebraska, Lincoln, Nebraska 68588-0299, USA, University of Nebraska - Lincoln

  • Balamurugan Balasubramanian

    Physics & Astronomy, University of Nebraska, Lincoln, Nebraska Center for Materials and Nanoscience and Department of Physics and Astronomy,, University of Nebraska, Lincoln, Nebraska 68588-0299, USA, University of Nebraska - Lincoln

  • Ahsan Ullah

    Nebraska Center for Materials and Nanoscience and Department of Physics and Astronomy,, University of Nebraska, Lincoln, Nebraska 68588-0299, USA, University of Nebraska - Lincoln

  • Rabindra Pahari

    Nebraska Center for Materials and Nanoscience and Department of Physics and Astronomy,, University of Nebraska, Lincoln, Nebraska 68588-0299, USA, University of Nebraska - Lincoln

  • David Sellmyer

    Physics & Astronomy, University of Nebraska, Lincoln, Nebraska Center for Materials and Nanoscience and Department of Physics and Astronomy,, University of Nebraska, Lincoln, Nebraska 68588-0299, USA, University of Nebraska - Lincoln, Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, United States