Magneto-Transport at Work: In-situ Transmission Electron Microscopy of Topological Spin Solitons

• Applicants: Dr. Darius Pohl, since 4/2024; Dr. Bernd Rellinghaus
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 403503416

The project addresses the general problem to directly relate (magneto-)transport properties to the nanoscopic details of the underlying magnetic textures of Skyrmions and related topological solitons determined in a transmission electron microscope. These two aspects are key to an in-depth understanding of the nature of these magnetic nano objects. To date, transport measurements are usually conducted on (macroscopic or mesoscopic) samples, whose size and morphology differ substantially from those investigated in a microscope. Since the stability of topological spin solitons sensitively depends on the size and thickness of the investigated materials, such ex-situ comparisons of samples of different dimensions are inherently problematic. Also the general question as to whether the tolological Hall and Nernst effects have their origin in the presence of Skyrmions is still under debate. These difficulties highlight the necessity to directly probe such correlations in in-situ experiments.So far, electrically biased in-situ experiments mainly aim at the mere observation of the current or field-induced motion of, e.g., Skyrmions, in order to phenomenologically understand their dynamics. These studies, however, do either not address the microscopic details of the topological objects, or the methodologically limited resolution does not allow for it. Within the framework of the first funding period, we have successfully performed the quantitative determination of spin textures in high-resolution 2D volume projections and 3D mappings in the transmission electron microscope. Consequently, we now aim at extending this work by the establishment of an experimental platform for in-situ measurements of magnetotransport properties in the microscope for the second funding period. Embedding these in-situ experiments in the priority program SPP-2137 creates substantial added value to the endeavor, as the research network of the program allows to interconnect our work with related (ex-situ) approaches in partnering projects, exchange both bulk and thin film samples, and thus connect the mesoscopic with the nanoscopic world down to even atomic length scales.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2137: Skyrmionics: Topological Spin Phenomena in Real-Space for Applications
• Ehemaliger Antragsteller: Privatdozent Dr. Andy Thomas, until 4/2024