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Non-periodic magnetic structure in chiral helimagnet Mn<sub>1/3</sub>NbS<sub>2</sub>

ORAL

Abstract

We have investigated the magnetic state of Mn1/3NbS2 through ac-magnetic susceptibility, Small-angle Neutron Scattering (SANS), Lorentz Transmission Electron Microscopy (LTEM) and micromagnetic simulations. The ac susceptibility displays temperature, field, and frequency dependencies which define a complex phase diagram below the critical temperature for magnetic ordering, TC = 45 K. SANS reveals a streak of magnetic scattering along the c-axis near Q = 0 appearing below TC, demonstrating a disordered ferromagnetic (FM) or helical spin ordering in this system. The width of this streak shortens and becomes more intense near TC and is gradually suppressed by the application of H along the beam. Micromagnetic simulations of thin lamella are in agreement with LTEM images of Mn1/3NbS2 where extended FM regions result from a shape anisotropy in thin samples that are separated by the chiral domain walls.

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Presenters

  • Sunil Karna

    Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Physics, Louisiana State University

Authors

  • Sunil Karna

    Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Physics, Louisiana State University

  • Michalis Charilaou

    Department of Physics, University of Louisiana at Lafayette

  • Andras Kovács

    Ernst Ruska–Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute,

  • Lisa DeBeer-Schmitt

    Oak Ridge National Laboratory, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA, Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge National Lab, Oak Ridge National Laboratory, Oak Ridge, USA

  • David P Young

    Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana State University, Baton Rouge, Physics, Louisiana State University

  • John Ditusa

    Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana State University, Baton Rouge, Physics, Louisiana State University