Physics-Informed Tomographic Imaging of Chiral Nanomagnets

• Applicant: Dr. Claire Donnelly
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 550057827

Three-dimensional chiral textures are of remarkable interest due to prospects for their topological stability, and complex behaviours, to provide new opportunities for technological devices. In order to understand, and control these textures, imaging of their three dimensional nanostructure is key. With first demonstrations of magnetic tomography by the proposers, it has been possible to gain direct access to complex three dimensional textures. However, there remain significant challenges in imaging chiral structures, due to the need for high spatial resolution, quantitative determination of material properties, and the ability to combine these with dynamic imaging, which is key to understanding and controlling their behaviour. The central aim of this project is to establish and apply new experimental and theoretical methods for the generation and observation of threedimensional chiral magnetic textures. We will investigate threedimensional topological textures in chiral bulk material as well as in curved 3D nanostructures. Key to our understanding of these complex systems is not only their 3D static configurations. We will leverage sparsity and physical constraints to extend our capabilities to the temporal domain, providing access to the dynamic behaviour of 3D chiral spin textures. At the core of this project is combining for the first time state-of-the art XMCD tomography with advanced physicsinformed reconstruction methods. This will not only significantly increase the effective spatial resolution and sensitivity, key for the accurate distinction of different chiral magnetic objects: in combination with the physical framework it will be possible to accurately determine various material properties, such as symmetric and antisymmetric coupling constants. In the course of this project we will design complex three-dimensional nano structures to host chiral magnetization textures. We will target two types of systems. First, we will fabricate achiral materials into chiral nanogeometries with FEBID. Secondly, we will pattern intrinsically chiral materials into simpler, curvilinear nanogeometries with focused-ion-beam milling. We will investigate their three-dimensional magnetisation configuration using the newly developed framework for physics-informed magnetic imaging. The methods developed within this project will significantly advance the field of three-dimensional magnetic imaging, establishing ultra-high spatial resolution imaging of topological textures to mapping complex magnetization dynamics. This will have far reaching implications for a wide variety of magnetic systems, from chiral to permanent magnets. To achieve this goal, the project brings together the unique expertise of four groups, namely the Abert group at UVIE (computational magnetism), the Donnelly group at MPI (three-dimensional nanomagnetism), the Guizar-Sicairos laboratory at EPFL (Computational X-ray Imaging) and the Fernandez-Pacheco Group at TU Wien (3D Nanofabrication).

• DFG Programme: Research Grants
• International Connection: Austria, Switzerland
• Partner Organisation: Schweizerischer Nationalfonds (SNF)
• Cooperation Partners: Privatdozent Dr. Claas Abert; Dr. Amalio Fernández-Pacheco; Professor Dr. Manuel Guizar-Sicairos