Realization of ordered magnetic skyrmions in thin films at ambient conditions

Ryan D. Desautels, Lisa DeBeer-Schmitt, Sergio A. Montoya, Julie A. Borchers, Soong-Geun Je, Nan Tang, Mi-Young Im, Michael R. Fitzsimmons, Eric E. Fullerton, and Dustin A. Gilbert

Phys. Rev. Materials 3, 104406 – Published 10 October 2019

Abstract

Magnetic skyrmions have captivated physicists due to their topological nature and novel physical properties. In addition, skyrmions hold significant promise for future information technologies. A key barrier to realizing skyrmion-based devices has been stabilizing these spin structures under ambient conditions. In this paper, we demonstrate that the tunable magnetic properties of amorphous Fe/Gd mulitlayers enable the formation of skyrmion lattices which are stable over a large temperature and magnetic field parameter space, including room temperature and zero magnetic field. These skyrmions, having a hybrid nature displaying both Bloch-type and Néel-type characteristics, are stabilized by dipolar interactions rather than Dzyaloshinskii-Moriya interactions, typically considered a requirement for the generation of skyrmions. Small angle neutron scattering (SANS) was used in combination with soft x-ray microscopy to provide a unique, multiscale probe of the local and long-range order of these structures. The hexagonal lattice seen in SANS results from the hybrid skyrmion picture obtained with micromagnetic simulations. These results identify a pathway to engineer controllable skyrmion phases in thin film geometries which are stable at ambient conditions.

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Received 30 April 2019

DOI:https://doi.org/10.1103/PhysRevMaterials.3.104406

Physics Subject Headings (PhySH)

Skyrmions Spin texture

Multilayer thin films Thin films

Small angle neutron scattering X-ray magnetic circular dichroism

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Ryan D. Desautels^* and Lisa DeBeer-Schmitt ^2,*

Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA

Sergio A. Montoya

Naval Information Warfare Center Pacific, San Diego, California 92152, USA

Julie A. Borchers

NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA

Soong-Geun Je

Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94270, USA

Nan Tang

Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA

Mi-Young Im

Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94270, USA; School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 03722, Republic of Korea; and Department of Emerging Materials Science, DGIST, Daegu 42988, Republic of Korea

Michael R. Fitzsimmons

Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA and Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA

Eric E. Fullerton

Center for Memory and Recording Research, University of California, San Diego, La Jolla, California 92093, USA

Dustin A. Gilbert

NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA and Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA