SPICE Workshop on Nanomagnetism in 3D, April 30th - May 2nd 2024
Vincent Cros
M. Grelier,1 R. Battistelli,2,6 S. Collin,1 A. Vecchiola,1 F. Godel,1 K. Bouzehouane,1 C. Donnelly,3 S. Finizio,5 K. Puzhekadavil Joy,2,6 F. Büttner,2,6 H. Popescu,4 N. Jaouen,4 N. Reyren1, V. Cros,1,*
1 Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
2 Helmholtz-Zentrum Berlin, Berlin, Germany
3 Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
4 Synchrotron SOLEIL, L’Orme des Merisiers, Gif-sur-Yvette, France.
5 Paul Scherrer Institut, Villigen PSI, Switzerland
6 Institüt für Physik, Universität Augsburg, Augsburg, Germany
*Vincent.cros@cnrs-thales.fr
Three-dimensional spin textures such as truncated skyrmions [1], bobbers [2] or even hopfions [3] emerge as promising quasi-particles for encoding information in future spintronic devices. The third dimension provides more malleability regarding their properties and more flexibility for potential applications. However, the stabilization and characterization of such quasi-particles in easily implementable systems remain a work in progress.
In this work, we show how by engineering Pt/Co/Al based multilayers with variable Co thickness, we observe the signature of new three dimensional spin textures, called skyrmionic cocoons [4] that are only present in a fraction of the magnetic layers. Interestingly, these 3D cocoons can coexist with more standard ‘tubular’ skyrmions going through all the multilayer as evidenced by the existence of two very different contrasts in the magnetic force microscopy (MFM) images recorded at room temperature that can be easily correlated with the corresponding micromagnetic simulations. One major shortcoming of studying 3D textures is the difficulty to access information about the bulk magnetization. To this end, we also performed magneto-transport measurements as well as X-ray Fourier Transform Holography, a transmission technique, in which we clearly observe different contrasts that thus corresponds to objects with various vertical extension. Moreover, we have also obtained a reconstruction of the magnetization, measured with X-ray laminography evidencing the different magnetic textures in our aperiodic multilayers. Their coexistence and the discovery of a novel magnetic texture are particularly interesting as they can open new paths for three-dimensional spintronics.
Acknowledgements
Financial supports from ANR-20-CE42-0012-01(MEDYNA), and ANR/DFG (Topo3D) and as part of the “Investissements d’Avenir" program SPiCY (ANR-10-LABX-0035).
References
[1] A.O. Mandru et al. Nature communications 11,1 (2020)
[2] F. Zheng et al. Nature Nanotechnology 13, 451 (2018)
[3] N. Kent et al. Nature communications 12, 1 (2021)
[4] M.Grelier, et al. Nature Communications 13.1 (2022): 6843.
[5] M.Grelier, et al. Physical Review B 107 (22), L220405 (2023)