The interference between the x-rays scattered through the reference slit, and those scattered through the sample, allows the phase difference SURFACES, INTERFACES AND NANOSYSTEMS SYNCHROTRON SOLEIL HIGHLIGHTS 2020 caused by the sample to be determined, and thus a real-space image can be reconstructed. Exposures using both left and right circularly polarised x-rays were measured. By subtracting these two diffraction patterns, and performing a Fourier transform, real-space images of the SEXTANTS BEAMLINE sample in each magnetic state were acquired, as shown in Fig. 2g-I. OBSERVING SKYRMION TUBES Associated publication Real-space imaging of confined By applying the magnetic field in-plane, one also expects to be able magnetic skyrmion tubes. to form skyrmions tubes in the plane of the lamella sample. We had success imaging this magnetic state when performing further scanning M. T. Birch, D. Cortés-Ortuño, transmission x-ray microscopy measurements using the MAXYMUS L. A. Turnbull, M. N. Wilson, F. Groß, instrument at the BESSY II synchrotron. With the magnetic field applied N. Träger, A. Laurenson, N. Bukin, S. H. Moody, M. Weigand, G. Schütz, left to right, Fig. 3a displays a magnetic contrast image of three pairs of H. Popescu, R. Fan, P. Steadman, light and dark horizontal stripes, which appear to show three magnetic J.A.T. Verezhak, G. Balakrishnan, skyrmion tubes embedded in a conical state background (vertical stripes). J. C. Loudon, A.C. Twitchett-Harrison, To validate the identity of these structure as skyrmion tubes, we performed O. Hovorka, H. Fangohr, F. Y. Ogrin, complimentary micromagnetic simulations of skyrmion tubes within a J. Gräfe, & P. D. Hatton. conical state background. The resulting simulated image, depicted in Fig. 3b, shows remarkable agreement to the experimental data. A three Nature Communications, 11: dimensional visualisation of the simulated magnetic state is shown in art.n° 1726 (2020). Fig. 3c, revealing the skyrmion tube structures. References FIGURE 3 [1] S. Mühlbauer etal. Science 323, 915, (2009). [2] N. Nagaosa etal. Nat. Nanotechnol. 8, 899 (2013). [3] P. Milde, et al., Science 340, 1076 (2013). [4] L. Turnbull, et al., ACS Nano 15, 387 (2021). [5] F. Kagawa, et al., Nat. Commun. 8, 1332 (2017). Corresponding author Peter D. Hatton Centre for Materials Physics, Durham University, Durham DH1 3LE, UK p.d.hatton@durham.ac.uk Captions FIGURE 1: Three-dimensional visualisation of three CONCLUSION magnetic skyrmion tubes, depicting the Bloch-point annihilation mechanism. The orientation of the applied The combination of multiple x-ray techniques employed at Diamond magnetic field, H, is indicated. Light Source, SOLEIL, and BESSY II, and the shared expertise of the FIGURE 2: a-c), Visualisations of the helical, UK Skyrmion Project members, collaborators from the University of skyrmion lattice and conical chiral spin textures. d-f), Exeter and the Max Planck Soceity, and the beamline scientists, was Corresponding diffraction patterns acquired for the three vital to the success of this project. Further investigations into the Bloch- magnetic states. g-i), Reconstructed real-space images of the magnetic states. point dynamics of skyrmion tubes – for example their current-induced FIGURE 3: a) Scanning transmission x-ray microscopy unwinding [5], will improve our understanding of skyrmion stability, image and b) simulated image of the skyrmion tube allowing future skyrmion read and write protocols to be optimised spin texture in a conical state background. c) Three- towards device applications. dimensional visualisation of the micromagnetic simulation. 25