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Title: Direct Demonstration of Topological Stability of Magnetic Skyrmions via Topology Manipulation

Abstract

Topological protection precludes a continuous deformation between topologically inequivalent configurations in a continuum. Motivated by this concept, magnetic skyrmions, topologically nontrivial spin textures, are expected to exhibit topological stability, thereby offering a prospect as a nanometer-scale nonvolatile information carrier. In real materials, however, atomic spins are configured as not continuous but discrete distributions, which raises a fundamental question if the topological stability is indeed preserved for real magnetic skyrmions. Answering this question necessitates a direct comparison between topologically nontrivial and trivial spin textures, but the direct comparison in one sample under the same magnetic fields has been challenging. Here we report how to selectively achieve either a skyrmion state or a topologically trivial bubble state in a single specimen and thereby experimentally show how robust the skyrmion structure is in comparison with the bubbles. We demonstrate that topologically nontrivial magnetic skyrmions show longer lifetimes than trivial bubble structures, evidencing the topological stability in a real discrete system. Our work corroborates the physical importance of the topology in the magnetic materials, which has hitherto been suggested by mathematical arguments, providing an important step toward ever-dense and more-stable magnetic devices.

Authors:
ORCiD logo [1];  [2]; ORCiD logo [3];  [4]; ORCiD logo [5];  [6];  [7];  [2]; ORCiD logo [8];  [9]; ORCiD logo [10]
  1. Chonnam National Univ., Gwangju (Korea, Republic of). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Center for X-ray Optics; Daegu Gyeongbuk Institute of Science and Technology (DGIST) (Korea, Republic of). Dept. of Emerging Materials Science; Korea Univ., Seoul (Korea, Republic of). Center for Spin-Orbitronic Materials
  2. Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of). School of Materials Science and Engineering
  3. Univ. of Missouri, Columbia, MO (United States). Dept. of Physics and Astronomy
  4. Space and Naval Warfare Systems Center Pacific, San Diego, CA (United States)
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Center for X-ray Optics
  6. Korea Univ., Seoul, (Korea, Rep. of). KU-KIST Graduate School of Converging Science and Technology
  7. Univ. of California, San Diego, CA (United States). Center for Memory and Recording Research; Univ. of California, San Diego, CA (United States). Dept. of Electrical and Computer Engineering
  8. Korea Univ., Seoul, (Korea, Rep. of). KU-KIST Graduate School of Converging Science and Technology; Korea Univ., Seoul, (Korea, Republic of). Dept. of Materials Science and Engineering
  9. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Center for X-ray Optics; Daegu Gyeongbuk Institute of Science and Technology (DGIST) (Korea, Republic of). Dept. of Emerging Materials Science; Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of). School of Materials Science and Engineering
  10. Daegu Gyeongbuk Institute of Science and Technology (DGIST) (Korea, Republic of). Dept. of Emerging Materials Science
Publication Date:
Research Org.:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC); Future Materials Discovery Program
OSTI Identifier:
1782142
Grant/Contract Number:  
AC02-05CH11231; NRF-2015M3D1A1070465; NRF-2017R1A2B4003139; NRF-2019R1A2C2002996.
Resource Type:
Accepted Manuscript
Journal Name:
ACS Nano
Additional Journal Information:
Journal Volume: 14; Journal Issue: 3; Journal ID: ISSN 1936-0851
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; topology manipulation; topological stability; topological protection; magnetic skyrmion; magnetic bubble; lifetime; FeGd

Citation Formats

Je, Soong-Geun, Han, Hee-Sung, Kim, Se Kwon, Montoya, Sergio A., Chao, Weilun, Hong, Ik-Sun, Fullerton, Eric E., Lee, Ki-Suk, Lee, Kyung-Jin, Im, Mi-Young, and Hong, Jung-Il. Direct Demonstration of Topological Stability of Magnetic Skyrmions via Topology Manipulation. United States: N. p., 2020. Web. doi:10.1021/acsnano.9b08699.
Je, Soong-Geun, Han, Hee-Sung, Kim, Se Kwon, Montoya, Sergio A., Chao, Weilun, Hong, Ik-Sun, Fullerton, Eric E., Lee, Ki-Suk, Lee, Kyung-Jin, Im, Mi-Young, & Hong, Jung-Il. Direct Demonstration of Topological Stability of Magnetic Skyrmions via Topology Manipulation. United States. https://doi.org/10.1021/acsnano.9b08699
Je, Soong-Geun, Han, Hee-Sung, Kim, Se Kwon, Montoya, Sergio A., Chao, Weilun, Hong, Ik-Sun, Fullerton, Eric E., Lee, Ki-Suk, Lee, Kyung-Jin, Im, Mi-Young, and Hong, Jung-Il. Wed . "Direct Demonstration of Topological Stability of Magnetic Skyrmions via Topology Manipulation". United States. https://doi.org/10.1021/acsnano.9b08699. https://www.osti.gov/servlets/purl/1782142.
@article{osti_1782142,
title = {Direct Demonstration of Topological Stability of Magnetic Skyrmions via Topology Manipulation},
author = {Je, Soong-Geun and Han, Hee-Sung and Kim, Se Kwon and Montoya, Sergio A. and Chao, Weilun and Hong, Ik-Sun and Fullerton, Eric E. and Lee, Ki-Suk and Lee, Kyung-Jin and Im, Mi-Young and Hong, Jung-Il},
abstractNote = {Topological protection precludes a continuous deformation between topologically inequivalent configurations in a continuum. Motivated by this concept, magnetic skyrmions, topologically nontrivial spin textures, are expected to exhibit topological stability, thereby offering a prospect as a nanometer-scale nonvolatile information carrier. In real materials, however, atomic spins are configured as not continuous but discrete distributions, which raises a fundamental question if the topological stability is indeed preserved for real magnetic skyrmions. Answering this question necessitates a direct comparison between topologically nontrivial and trivial spin textures, but the direct comparison in one sample under the same magnetic fields has been challenging. Here we report how to selectively achieve either a skyrmion state or a topologically trivial bubble state in a single specimen and thereby experimentally show how robust the skyrmion structure is in comparison with the bubbles. We demonstrate that topologically nontrivial magnetic skyrmions show longer lifetimes than trivial bubble structures, evidencing the topological stability in a real discrete system. Our work corroborates the physical importance of the topology in the magnetic materials, which has hitherto been suggested by mathematical arguments, providing an important step toward ever-dense and more-stable magnetic devices.},
doi = {10.1021/acsnano.9b08699},
journal = {ACS Nano},
number = 3,
volume = 14,
place = {United States},
year = {Wed Mar 04 00:00:00 EST 2020},
month = {Wed Mar 04 00:00:00 EST 2020}
}

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