Topologically protected magnetic textures are promising candidates for information carriers in future memory devices, as they can be efficiently propelled at very high velocities using current-induced spin torques. These textures-nanoscale whirls in the magnetic order-include skyrmions, half-skyrmions (merons) and their antiparticles. Antiferromagnets have been shown to host versions of these textures that have high potential for terahertz dynamics, deflection-free motion and improved size scaling due to the absence of stray field. Here we show that topological spin textures, merons and antimerons, can be generated at room temperature and reversibly moved using electrical pulses in thin-film CuMnAs, a semimetallic antiferromagnet that is a testbed system for spintronic applications. The merons and antimerons are localized on 180° domain walls, and move in the direction of the current pulses. The electrical generation and manipulation of antiferromagnetic merons is a crucial step towards realizing the full potential of antiferromagnetic thin films as active components in high-density, high-speed magnetic memory devices.

Diamond Light Source Chilton UK

Institut für Physik Johannes Gutenberg Universität Mainz Mainz Germany

Institute of Physics Czech Academy of Sciences Prague Czech Republic

School of Physics and Astronomy University of Nottingham Nottingham UK

School of Physics The University of New South Wales Sydney New South Wales Australia

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Kosterlitz JM, Thouless DJ. Ordering, metastability and phase transitions in two-dimensional systems. J. Phys. C. 1973;6:1181. doi: 10.1088/0022-3719/6/7/010. PubMed DOI

Shinjo T, Okuno T, Hassdorf R, Shigeto K, Ono T. Magnetic vortex core observation in circular dots of permalloy. Science. 2000;289:930–932. doi: 10.1126/science.289.5481.930. PubMed DOI

Kläui M, et al. Current-induced vortex nucleation and annihilation in vortex domain walls. Appl. Phys. Lett. 2006;88:232507. doi: 10.1063/1.2209177. DOI

Jiang W, et al. Blowing magnetic skyrmion bubbles. Science. 2015;349:283–286. doi: 10.1126/science.aaa1442. PubMed DOI

Coïsson M. Magnetic vortex chirality determination via local hysteresis loops measurements with magnetic force microscopy. Sci. Rep. 2016;6:29904. doi: 10.1038/srep29904. PubMed DOI PMC

Gao N, et al. Creation and annihilation of topological meron pairs in in-plane magnetized films. Nat. Commun. 2019;10:5603. doi: 10.1038/s41467-019-13642-z. PubMed DOI PMC

Gao Y, et al. Spontaneous (anti)meron chains in the domain walls of van der Waals ferromagnetic Fe5−xGeTe2. Adv. Mater. 2020;32:2005228. doi: 10.1002/adma.202005228. PubMed DOI

Li Z, et al. Field-free topological behavior in the magnetic domain wall of ferrimagnetic GdFeCo. Nat. Commun. 2021;12:5604. doi: 10.1038/s41467-021-25926-4. PubMed DOI PMC

Wang Y, et al. Electric field-driven rotation of magnetic vortex originating from magnetic anisotropy reorientation. Adv. Electron. Mater. 2021;8:2100561. doi: 10.1002/aelm.202100561. DOI

Zhang S, et al. Direct imaging of an inhomogeneous electric current distribution using the trajectory of magnetic half-skyrmions. Sci. Adv. 2020;6:eaay1876. doi: 10.1126/sciadv.aay1876. PubMed DOI PMC

Göbel B, Mook A, Henk J, Mertig I, Tretiakov OA. Magnetic bimerons as skyrmion analogues in in-plane magnets. Phys. Rev. B. 2019;99:060407. doi: 10.1103/PhysRevB.99.060407. DOI

Göbel B, Mertig I, Tretiakov OA. Beyond skyrmions: review and perspectives of alternative magnetic quasiparticles. Phys. Rep. 2021;895:1–28. doi: 10.1016/j.physrep.2020.10.001. DOI

Barker J, Tretiakov OA. Static and dynamical properties of antiferromagnetic skyrmions in the presence of applied current and temperature. Phys. Rev. Lett. 2016;116:147203. doi: 10.1103/PhysRevLett.116.147203. PubMed DOI

Thiele AA. Steady-state motion of magnetic domains. Phys. Rev. Lett. 1973;30:230–233. doi: 10.1103/PhysRevLett.30.230. DOI

Tretiakov OA, et al. Dynamics of domain walls in magnetic nanostrips. Phys. Rev. Lett. 2008;100:127204. doi: 10.1103/PhysRevLett.100.127204. PubMed DOI

Tveten EG, Qaiumzadeh A, Tretiakov OA, Brataas A. Staggered dynamics in antiferromagnets by collective coordinates. Phys. Rev. Lett. 2013;110:127208. doi: 10.1103/PhysRevLett.110.127208. PubMed DOI

Kolesnikov AG, et al. Composite topological structure of domain walls in synthetic antiferromagnets. Sci. Rep. 2018;8:15794. doi: 10.1038/s41598-018-33780-6. PubMed DOI PMC

Sort J, et al. Imprinting vortices into antiferromagnets. Phys. Rev. Lett. 2006;97:067201. doi: 10.1103/PhysRevLett.97.067201. PubMed DOI

Wu J, et al. Direct observation of imprinted antiferromagnetic vortex states in CoO/Fe/Ag(001) discs. Nat. Phys. 2011;7:303–306. doi: 10.1038/nphys1891. DOI

Chmiel FP, et al. Observation of magnetic vortex pairs at room temperature in a planar α-Fe2O3/Co heterostructure. Nat. Mater. 2018;17:581–585. doi: 10.1038/s41563-018-0101-x. PubMed DOI

Gao S, et al. Fractional antiferromagnetic skyrmion lattice induced by anisotropic couplings. Nature. 2020;586:37–41. doi: 10.1038/s41586-020-2716-8. PubMed DOI

Jani H, et al. Antiferromagnetic half-skyrmions and bimerons at room temperature. Nature. 2021;590:74–79. doi: 10.1038/s41586-021-03219-6. PubMed DOI

Wadley P, et al. Electrical switching of an antiferromagnet. Science. 2016;351:587–590. doi: 10.1126/science.aab1031. PubMed DOI

Grzybowski MJ, et al. Imaging current-induced switching of antiferromagnetic domains in CuMnAs. Phys. Rev. Lett. 2017;118:057701. doi: 10.1103/PhysRevLett.118.057701. PubMed DOI

Olejník K, et al. Antiferromagnetic CuMnAs multi-level memory cell with microelectronic compatibility. Nat. Commun. 2017;8:15434. doi: 10.1038/ncomms15434. PubMed DOI PMC

Olejník K, et al. Terahertz electrical writing speed in an antiferromagnetic memory. Sci. Adv. 2018;4:eaar3566. doi: 10.1126/sciadv.aar3566. PubMed DOI PMC

Wadley P, et al. Current polarity-dependent manipulation of antiferromagnetic domains. Nat. Nanotechnol. 2018;13:362–365. doi: 10.1038/s41565-018-0079-1. PubMed DOI

Kašpar Z, et al. Quenching of an antiferromagnet into high resistivity states using electrical or ultrashort optical pulses. Nat. Electron. 2021;4:30–37. doi: 10.1038/s41928-020-00506-4. DOI

Zubáč J, et al. Hysteretic effects and magnetotransport of electrically switched CuMnAs. Phys. Rev. B. 2021;104:184424. doi: 10.1103/PhysRevB.104.184424. DOI

Krizek F, et al. Molecular beam epitaxy of CuMnAs. Phys. Rev. Mater. 2020;4:014409. doi: 10.1103/PhysRevMaterials.4.014409. DOI

Janda T, et al. Magneto-Seebeck microscopy of domain switching in collinear antiferromagnet CuMnAs. Phys. Rev. Mater. 2020;4:094413. doi: 10.1103/PhysRevMaterials.4.094413. DOI

Wadley P, et al. Control of antiferromagnetic spin axis orientation in bilayer Fe/CuMnAs films. Sci. Rep. 2017;7:11147. doi: 10.1038/s41598-017-11653-8. PubMed DOI PMC

Reimers S, et al. Defect-driven antiferromagnetic domain walls in CuMnAs films. Nat. Commun. 2022;13:724. doi: 10.1038/s41467-022-28311-x. PubMed DOI PMC

Máca F, et al. Physical properties of the tetragonal CuMnAs: a first-principles study. Phys. Rev. B. 2017;96:094406. doi: 10.1103/PhysRevB.96.094406. DOI

Kurebayashi D, Tretiakov OA. Skyrmion nucleation on the surface of a topological insulator. Phys. Rev. Res. 2022;4:043105. doi: 10.1103/PhysRevResearch.4.043105. DOI

Hertel R, Schneider CM. Exchange explosions: magnetization dynamics during vortex–antivortex annihilation. Phys. Rev. Lett. 2006;97:177202. doi: 10.1103/PhysRevLett.97.177202. PubMed DOI

Gomonay O, Jungwirth T, Sinova J. High antiferromagnetic domain wall velocity induced by Néel spin–orbit torques. Phys. Rev. Lett. 2016;117:017202. doi: 10.1103/PhysRevLett.117.017202. PubMed DOI

Tomasello R, et al. A strategy for the design of skyrmion racetrack memories. Sci. Rep. 2014;4:6784. doi: 10.1038/srep06784. PubMed DOI PMC

Geng LD, Jin YM. Magnetic vortex racetrack memory. J. Magn. Magn. Mater. 2017;423:84–89. doi: 10.1016/j.jmmm.2016.09.062. DOI

Juge R, et al. Helium ions put magnetic skyrmions on the track. Nano Lett. 2021;21:2989–2996. doi: 10.1021/acs.nanolett.1c00136. PubMed DOI

Yu H, Xiao J, Schultheiss H. Magnetic texture based magnonics. Phys. Rep. 2021;905:1–59. doi: 10.1016/j.physrep.2020.12.004. DOI

Nanoscale imaging and control of altermagnetism in MnTe