Direct observation of magnetic states in an actinide ferromagnet UMn<sub>2</sub>Ge<sub>2</sub>

ORAL

Abstract

We present studies of the magnetic domain structure of UMn2Ge2 single crystals using a home-built low temperature magnetic force microscope. The material has two distinct magnetic ordering temperatures, originating from the Mn and U moments. At room temperature, where the Mn moments dominate, flower-like domain patterns are observed. After exposing the sample to a one-tesla magnetic field near 40K, the evolution of the magnetic domains is imaged through zero field warming up to 200 K. Near the ordering temperature of the uranium moments a clear change in the domain wall motion is observed and can be explained by a 'Slingshot' mechanism. The anti-ferromagnetic coupling between Mn and U moments, responsible for the rapid domain wall motion, is further verified by local magnetic roughness measurement. The domain size analysis of the flower-like pattern reveals that the domain structure is consistent with a model of branching domains. In addition, an in-plane anisotropy is identified to be responsible for the highly self-similar flower-like pattern. Finally, there is also evidence of nanometer scale sub-domain structure inside each branching domain, comparable with what has been reported on uniaxial magnetic material Nd2Fe14B.

*Supported by NSF DMR-1507874 and DOE

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Presenters

  • Xinzhou Tan

    • Department of Physics, Univ of Texas

Authors

  • Xinzhou Tan

    • Department of Physics, Univ of Texas

  • Alejandro De Lozanne

    • Department of Physics, Univ of Texas

  • Morgann Berg

    • Sandia National Laboratory

  • Jeehoon Kim

    • Department of Physics, Pohang University of Science and Technology

  • Ryan Baumbach

    • National High Magnetic Field Laboratory, Florida State University
    • National High Magnetic Field Lab, Florida State University
    • National High Magnetic Field Laboratory
    • NHMFL
    • National High Magnetic Field Laboratory/Florida State University
    • Natl High Magnetic Field Lab
    • NHMFL at Florida State University

  • Eric Bauer

    • MPA-CMMS, Los Alamos National Laboratory
    • Los Alamos National Laboratory
    • Los Alamos Natl Lab
    • Condensed Matter and Magnetic Science Group, Los Alamos National Laboratory
    • Los Alamos National Lab
    • Condensed Matter and Magnet Science Group, Los Alamos National Laboratory

  • Joe Thompson

    • MPA-CMMS, Los Alamos National Laboratory
    • Los Alamos National Laboratory
    • Condensed Matter and Magnetic Science Group, Los Alamos National Laboratory
    • Los Alamos Natl Lab
    • Condensed Matter and Magnet Science Group, Los Alamos National Laboratory

  • Filip Ronning

    • MPA-CMMS, Los Alamos National Laboratory
    • Los Alamos Natl Lab
    • Los Alamos National Laboratory
    • Condensed Matter and Magnetic Science Group, Los Alamos National Laboratory
    • Condensed Matter and Magnet Science Group, Los Alamos National Laboratory