Search for magnetochiral responses in curvilinear Geometries
Theoretical Condensed Matter Physics
Final Report Abstract
The interplay between geometry and topology of the order parameter is a fundamental problem of soft and condensed matter physics. Much attention is dedicated to strongly correlated electronic systems as they provide a unique tool to manipulate the topology of coexisting vector fields through geometrical parameters. In magnetism, geometrical effects were traditionally addressed via boundary design, which introduces shape anisotropies and enables the formation of non-trivial magnetic textures. However, recent advancements in fabrication and microscopy now allow direct control over magnetic states by designing threedimensional (3D) geometries. Still, despite numerous experimental trials, magnetic responses from 3D architectures remained complex and insufficiently understood. The ultimate goal of this project was to develop a fundamental understanding of curvature-induced magnetochiral responses in curvilinear magnets and explore their influence on topologically nontrivial textures. To achieve this, we extended the theoretical framework of curvilinear magnetism to 3D nanomagnets and experimentally revealed the appearance of non-local chiral symmetrybreaking effects induced by magnetostatic interactions. Using advanced microscopy techniques in combination with theoretical predictions, we showed that the vortex core in asymmetric nanodots exhibits a homochiral curling deformation with nonzero curvature and torsion. Moreover, there is a mutual link between the chirality of the vortex string and the magnetic helicity of the texture. These two magnetochiral properties are linked as the sign of the torsion of the vortex string is determined by the direction of the circulation of the in-plane magnetization component of the vortex for the given polarity. Thus, vortex textures in 3D curvilinear systems are governed by multiple, interlinked magnetochiral parameters. Within the project, we also introduced and validated a strategy to realize complex magnetic textures with high total vorticity in equilibrium. Using state-of-the-art magnetic X-ray microscopy, we showed that free-standing magnetic wireframes obtain a predictable number of solitons defined by the topological Euler characteristic of the geometry. By tuning the genus through structural modifications (e.g., by introducing holes), it is possible to obtain a predefined number of solitons of a given vorticity. Overall, this project revealed a novel symmetry-breaking mechanism driven purely by geometrical asymmetry in intrinsically achiral magnets. In addition to geometric topologicallydriven effects, it paves the way for new directions in 3D spintronics and topological magnetism. The results have been published in high-impact journals and presented at key national and international conferences.
Publications
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New Dimension in Magnetism and Superconductivity: 3D and Curvilinear Nanoarchitectures. Advanced Materials, 34(3).
Makarov, Denys; Volkov, Oleksii M.; Kákay, Attila; Pylypovskyi, Oleksandr V.; Budinská, Barbora & Dobrovolskiy, Oleksandr V.
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Electronic materials with nanoscale curved geometries. Nature Electronics, 5(9), 551-563.
Gentile, Paola; Cuoco, Mario; Volkov, Oleksii M.; Ying, Zu-Jian; Vera-Marun, Ivan J.; Makarov, Denys & Ortix, Carmine
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Fundamentals of Curvilinear Ferromagnetism: Statics and Dynamics of Geometrically Curved Wires and Narrow Ribbons. Small, 18(12).
Sheka, Denis D.; Pylypovskyi, Oleksandr V.; Volkov, Oleksii M.; Yershov, Kostiantyn V.; Kravchuk, Volodymyr P. & Makarov, Denys
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Chirality coupling in topological magnetic textures with multiple magnetochiral parameters. Nature Communications, 14(1).
Volkov, Oleksii M.; Wolf, Daniel; Pylypovskyi, Oleksandr V.; Kákay, Attila; Sheka, Denis D.; Büchner, Bernd; Fassbender, Jürgen; Lubk, Axel & Makarov, Denys
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Site-Selective Chemical Vapor Deposition on Direct-Write 3D Nanoarchitectures. ACS Nano, 17(5), 4704-4715.
Porrati, Fabrizio; Barth, Sven; Gazzadi, Gian Carlo; Frabboni, Stefano; Volkov, Oleksii M.; Makarov, Denys & Huth, Michael
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Three-dimensional magnetic nanotextures with high-order vorticity in soft magnetic wireframes. Nature Communications, 15(1).
Volkov, Oleksii M.; Pylypovskyi, Oleksandr V.; Porrati, Fabrizio; Kronast, Florian; Fernandez-Roldan, Jose A.; Kákay, Attila; Kuprava, Alexander; Barth, Sven; Rybakov, Filipp N.; Eriksson, Olle; Lamb-Camarena, Sebastian; Makushko, Pavlo; Mawass, Mohamad-Assaad; Shakeel, Shahrukh; Dobrovolskiy, Oleksandr V.; Huth, Michael & Makarov, Denys
