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ABSTRACT Crystal lattices with tetragonal or hexagonal structure often exhibit structural transitions in response to external stimuli1. Similar behaviour is anticipated for the lattice forms

of topological spin textures, such as lattices composed of merons and antimerons or skyrmions and antiskyrmions (types of vortex related to the distribution of electron spins in a magnetic

field), but has yet to be verified experimentally2,3. Here we report real-space observations of spin textures in a thin plate of the chiral-lattice magnet Co8Zn9Mn3, which exhibits in-plane

magnetic anisotropy. The observations demonstrate the emergence of a two-dimensional square lattice of merons and antimerons from a helical state, and its transformation into a hexagonal

lattice of skyrmions in the presence of a magnetic field at room temperature. Sequential observations with decreasing temperature reveal that the topologically protected skyrmions remain

robust to changes in temperature, whereas the square lattice of merons and antimerons relaxes to non-topological in-plane spin helices, highlighting the different topological stabilities of

merons, antimerons and skyrmions. Our results demonstrate the rich variety of topological spin textures and their lattice forms, and should stimulate further investigation of emergent

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SIMILAR CONTENT BEING VIEWED BY OTHERS PHASE SHIFT IN SKYRMION CRYSTALS Article Open access 01 December 2021 MULTISTEP TOPOLOGICAL TRANSITIONS AMONG MERON AND SKYRMION CRYSTALS IN A

CENTROSYMMETRIC MAGNET Article 01 April 2024 TRANSITION BETWEEN DISTINCT HYBRID SKYRMION TEXTURES THROUGH THEIR HEXAGONAL-TO-SQUARE CRYSTAL TRANSFORMATION IN A POLAR MAGNET Article Open

access 05 December 2023 DATA AVAILABILITY The data shown in the figures and that support the findings of this study are available from the corresponding author on reasonable request.

REFERENCES * Kittle, C. _Introduction to Solid State Physics_ Ch. 1 (John Wiley & Sons, New York, (2005). Google Scholar  * Lin, S. Z., Saxena, A. & Batista, C. D. Skyrmion

fractionalization and merons in chiral magnets with easy-plane anisotropy. _Phys. Rev. B_ 91, 224407 (2015). Article  ADS  Google Scholar  * Yi, S. D., Onoda, S., Nagaosa, N. & Han, J.

H. Skyrmions and anomalous Hall effect in a Dzyaloshinskii–Moriya spiral magnet. _Phys. Rev. B_ 80, 054416 (2009). Article  ADS  Google Scholar  * Berdiyorov, G. R., Milošević, M. V. &

Peeters, F. M. Vortex configurations and critical parameters in superconducting thin films containing antidote arrays: nonlinear Ginzburg−Landau theory. _Phys. Rev. B_ 74, 174512 (2006).

Article  ADS  Google Scholar  * Mühlbauer, S. et al. Skyrmion lattice in a chiral magnet. _Science_ 323, 915–919 (2009). Article  ADS  Google Scholar  * Yu, X. Z. et al. Real-space

observation of a two-dimensional skyrmion crystal. _Nature_ 465, 901–904 (2010). Article  ADS  CAS  Google Scholar  * Nagaosa, N. & Tokura, Y. Topological properties and dynamics of

magnetic skyrmions. _Nat. Nanotechnol_. 8, 899–911 (2013). Article  ADS  CAS  Google Scholar  * Tokunaga, Y. et al. A new class chiral materials hosting magnetic skyrmions beyond room

temperature. _Nat. Commun_. 6, 7638 (2015). Article  ADS  CAS  Google Scholar  * Heinze, S. et al. Spontaneous atomic-scale magnetic skyrmion lattice in two dimensions. _Nat. Phys_. 7,

713–718 (2011). Article  CAS  Google Scholar  * Kézsmárki, I. et al. Néel-type skyrmion lattice with confined orientation in the polar magnetic semiconductor GaV4S8. _Nat. Mater_. 14,

1116–1122 (2015). Article  ADS  Google Scholar  * Li, W. et al. Emergence of skyrmions from rich parent phases in the molybdenum nitrides. _Phys. Rev. B_ 93, 060409(R) (2016). Article  ADS 

Google Scholar  * Woo, S. et al. Observation of room-temperature magnetic skyrmions and their current-driven dynamics in ultrathin metallic ferromagnets. _Nat. Mater_. 15, 501–506 (2016).

Article  ADS  CAS  Google Scholar  * Jiang, W. et al. Blowing magnetic skyrmion bubbles. _Science_ 349, 283–286 (2015). Article  ADS  CAS  Google Scholar  * Sampaio, J., Cros, V., Rohart,

S., Thiaville, A. & Fert, A. Nucleation, stability and current-induced motion of isolated magnetic skyrmions in nanostructures. _Nat. Nanotechnol_. 8, 839–844 (2013). Article  ADS  CAS 

Google Scholar  * Zheng, F. S. et al. Experimental observation of chiral magnetic bobbers in B20-type FeGe. _Nat. Nanotechnol_. 13, 451–455 (2018). Article  ADS  CAS  Google Scholar  *

Nayak, A. K. et al. Magnetic antiskyrmions above room temperature in tetragonal Heusler materials. _Nature_ 548, 561–566 (2017). Article  ADS  CAS  Google Scholar  * Ozawa, R. et al. Vortex

crystals with chiral stripes in itinerant magnets. _J. Phys. Soc. Jpn_ 85, 103703 (2016). Article  ADS  Google Scholar  * Vousden, M. et al. Skyrmions in thin films with easy-plane

magnetocrystalline anisotropy. _Appl. Phys. Lett_. 108, 132406 (2016). Article  ADS  Google Scholar  * Shinjo, T., Okuno, T., Hassdorf, R., Shigeko, K. & Ono, T. Magnetic vortex core

observation in circular dots of permalloy. _Science_ 289, 930–932 (2000). Article  ADS  CAS  Google Scholar  * Phatak, C., Petford-Long, A. K. & Heinonen, O. Direct observation of

unconventional topological spin structure in coupled magnetic discs. _Phys. Rev. Lett_. 108, 067205 (2012). Article  ADS  CAS  Google Scholar  * Wintz, S. et al. Topology and origin of

effective spin meron pairs in ferromagnetic multilayer elements. _Phys. Rev. Lett_. 110, 177201 (2013). Article  ADS  Google Scholar  * Tan, A. et al. Topology of spin meron pairs in coupled

Ni/Fe/Co/Cu (001) disks. _Phys. Rev. B_ 94, 014433 (2016). Article  ADS  Google Scholar  * Ishizuka, K. & Allman, B. Phase measurement in electron microscopy using the transport of

intensity equation. _J. Electron Microsc_. 54, 191–197 (2005). CAS  Google Scholar  * Shibata, K. et al. Large anisotropic deformation of skyrmions in strained crystals. _Nat. Nanotechnol_.

10, 589–592 (2015). Article  ADS  CAS  Google Scholar  * Karube, K. et al. Robust metastable skyrmions and their triangular–square lattice structural transition in a high-temperature chiral

magnet. _Nat. Mater_. 15, 1237–1242 (2016). Article  ADS  CAS  Google Scholar  * Nakajima, T. et al. Skyrmion lattice structural transition in MnSi. _Sci. Adv_. 3, e1602562 (2017). Article 

ADS  Google Scholar  * Oike, H. et al. Interplay between topological and thermodynamic stability in a metastable magnetic skyrmion lattice. _Nat. Phys_. 12, 62–66 (2016). Article  CAS 

Google Scholar  * Münzer, W. et al. Skyrmion lattice in the doped semiconductor Fe1−_x_Co_x_Si. _Phys. Rev. B_ 81, 041203(R) (2010). Article  ADS  Google Scholar  * Yu, X. Z. et al.

Aggregation and collapse dynamics of skyrmions in a non-equilibrium state. _Nat. Phys_. 14, 832–836 (2018). Article  CAS  Google Scholar  * Yu, X. Z. et al. Current−induced nucleation and

annihilation of magnetic skyrmions at room temperature in a chiral magnet. _Adv. Mater_. 29, 1606178 (2017). Article  Google Scholar  * Beleggia, M. et al. Quantitative study of magnetic

field distribution by electron holography and micromagnetic simulations. _Appl. Phys. Lett_. 83, 1435 (2003). Article  ADS  CAS  Google Scholar  * Morikawa, D. et al. Deformation of

topologically-protected supercooled skyrmions in a thin plate of chiral magnet Co8Zn8Mn4. _Nano Lett_. 17, 1637–1641 (2017). Article  ADS  CAS  Google Scholar  * Bogdanov, A. & Hubert,

A. Thermodynamically stable magnetic vortex states in magnetic crystals. _J. Magn. Magn. Mater_. 138, 255–269 (1994). Article  ADS  CAS  Google Scholar  * Hubert, A. & Schäfer, R.

_Magnetic Domains_ Chs. 2, 3 (Springer, Berlin, 1998). Google Scholar  Download references ACKNOWLEDGEMENTS We thank M. Ishida, Á. Butykai, D. Morikawa, T-H. Arima and M. V. Mostovoy for

experimental support and discussions. N.N. was supported by JSPS KAKENHI (grant numbers JP26103006 and JP18H03676) and JST CREST (grant number JPMJCR1874), Japan. REVIEWER INFORMATION

_Nature_ thanks S. Woo and the other anonymous reviewers for their contribution to the peer review of this work. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * RIKEN Center for Emergent

Matter Science (CEMS), Wako, Japan X. Z. Yu, W. Koshibae, K. Shibata, Y. Taguchi, N. Nagaosa & Y. Tokura * Department of Advanced Materials Science, University of Tokyo, Kashiwa, Japan

Y. Tokunaga * Department of Applied Physics, University of Tokyo, Tokyo, Japan N. Nagaosa & Y. Tokura Authors * X. Z. Yu View author publications You can also search for this author

inPubMed Google Scholar * W. Koshibae View author publications You can also search for this author inPubMed Google Scholar * Y. Tokunaga View author publications You can also search for this

author inPubMed Google Scholar * K. Shibata View author publications You can also search for this author inPubMed Google Scholar * Y. Taguchi View author publications You can also search

for this author inPubMed Google Scholar * N. Nagaosa View author publications You can also search for this author inPubMed Google Scholar * Y. Tokura View author publications You can also

search for this author inPubMed Google Scholar CONTRIBUTIONS Y. Tokura conceived the project. X.Z.Y. performed Lorentz TEM and analysed the experimental data. W.K. and N.N. performed the

theoretical analyses. Y. Tokunaga and Y. Taguchi synthesized the Co-Zn-Mn alloys. K.S. simulated the Lorentz TEM images. All authors discussed the data and collaborated on the manuscript.

CORRESPONDING AUTHOR Correspondence to X. Z. Yu. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing interests. ADDITIONAL INFORMATION PUBLISHER’S NOTE: Springer Nature

remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. EXTENDED DATA FIGURES AND TABLES EXTENDED DATA FIG. 1 THE CRYSTAL STRUCTURE, MAGNETIC

CONFIGURATIONS AND MAGNETIC PHASE DIAGRAMS OF THE (001) THIN PLATE OF CO8ZN9MN3. A, B, Schematics of the crystal structure with space group _P_4132 (A) and _P_4332 (B). Coloured arrows

indicate the crystal axes. C, Magnetic phase diagram (approximate) of the hex-SkL30 and sq-ML observed over field-increasing runs from low (less than 10 mT) field cooling for a (001) thin

plate of Co8Zn9Mn3. The phase determination was based on the continuous magnetic-field scans at fixed temperatures in intervals of Δ_T_ = 5 K. The arrow indicates the field-increasing run

for the Lorentz TEM images shown in Fig. 2a–c. FM, field-magnetized ferromagnetic structure. D, E, Periodic stripe domains with a single wavevector along the [100] axis at 95 K (D), the

helical structure with possible multi-domains composed of helices with in-plane wavevectors (area B) and with out-of-plane wavevectors (dark regions; area A) at 295 K (E), respectively. F, A

hex-SkL realized under 65 mT at 300 K. Colours in D–F (see colour wheel) depict the direction (white arrows) of the local in-plane magnetization; black shows the out-of-plane magnetization.

EXTENDED DATA FIG. 2 THE APPROXIMATE IN-PLANE MAGNETIZATION TEXTURES AND SIMULATED DEFOCUSED LORENTZ TEM IMAGES. A, D, H, sq-ML. B, E, I, sq-SkL. C, F, J, hex-SkL. The parameters for the

simulations are shown in Extended Data Table 1. The colour bar indicates the normalized component of the out-of-plane magnetization _m_z. EXTENDED DATA FIG. 3 MAGNETIC PHASE DIAGRAMS AND

SEVERAL OVER-FOCUSED LORENTZ TEM IMAGES OBSERVED IN THE (001) THIN PLATE OF CO8ZN9MN3 WITH VARYING TEMPERATURE _T_ AND EXTERNAL MAGNETIC FIELD _B_. A, Phase diagram of the magnetic structure

observed after 60-mT field cooling with increasing _B_ (red dashed arrows), decreasing (black arrow) _B_ and then increasing _T_ (blue dashed arrow). B, Phase diagram of the magnetic

structure observed after field cooling with various cooling fields (indicated by red dashed arrows). H + M shows the mixed structure of helices (dominant) and merons (minor). The open

circles specify the (_T_, _B_) points that we measured. The dark blue region shows the helical phase. C–F, Over-focused Lorentz TEM images observed for different _T_ and _B_, indicated by

black solid circles in A (C, D) and yellow solid circles in B (E, F). EXTENDED DATA FIG. 4 VARIOUS PERIODIC ARRAYS OF THE TOPOLOGICAL SPIN TEXTURES OBSERVED IN THE (001) THIN PLATE OF

CO8ZN9MN3 WITH VARYING EXTERNAL MAGNETIC FIELD. A, B, D, E, G, H, Lorentz TEM images (A, D and G; insets show the corresponding fast Fourier transforms) and their magnetization maps (B, E

and H) for the sq-ML (A, B), hex-SkL (D, E) and skyrmion chains (G, H) observed at 295 K and various fields. C, F, I, Magnified magnetization textures in the boxed areas in B, E and H.

EXTENDED DATA FIG 5 SPONTANEOUS MAGNETIC STRUCTURES IN THIN PLATES OF CO-ZN-MN WITH VARIOUS MN COMPOSITIONS. A–H, Defocused Lorentz TEM images observed in the thin plates of Co-Zn-Mn at zero

field and 95 K. I–L, Electron-phase images obtained from analysing Lorentz TEM images in A–H with the transport-of-intensity equation. EXTENDED DATA FIG. 6 EXOTIC TOPOLOGICAL SPIN TEXTURES

IN THIN PLATES OF CO-ZN-MN WITH VARIOUS MN COMPOSITIONS. A–C, Over-focused Lorentz TEM images of skyrmion chains observed in Co8Zn9Mn3 (A), bound skyrmions in Co8Zn10Mn2 (B; such as that

indicated by the yellow arrow) and bubble-like domains in CoZn (C; such as that indicated by the white arrow). SUPPLEMENTARY INFORMATION VIDEO 1 An in-situ Lorentz TEM video showing

transitions of magnetic configurations from the helical structure to a hexagonal lattice of skyrmion, via a square lattice of meron and antimeron in a (001) thin plate of Co8Zn9Mn3 with an

increasing run of the magnetic bias field. RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Yu, X.Z., Koshibae, W., Tokunaga, Y. _et al._ Transformation

between meron and skyrmion topological spin textures in a chiral magnet. _Nature_ 564, 95–98 (2018). https://doi.org/10.1038/s41586-018-0745-3 Download citation * Received: 12 July 2018 *

Accepted: 11 October 2018 * Published: 05 December 2018 * Issue Date: 06 December 2018 * DOI: https://doi.org/10.1038/s41586-018-0745-3 SHARE THIS ARTICLE Anyone you share the following link

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content-sharing initiative KEYWORDS * Spin Texture * Co Zn Mn * Skyrmion Lattice * Dzyaloshinskii-Moriya Interaction * Fresnel Image