Mesoscopic topological spin textures, spin and topological Hall effect in magnetic thin films and heterostructures

• Applicant: Professorin Dr. Claudia Felser
• Subject Area: Experimental Condensed Matter Physics ; Synthesis and Properties of Functional Materials
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 403502666

Topological spin textures in quantum materials are of great interest, along with the associated transport signatures, for next-generation spintronic applications. The most important phenomenon is the topological Hall effect (THE), which has a distinct signature for each topological texture. Generally, the THE is determined by the size of the magnetic texture and the coupling strength of the charge carriers to it.Within the present project, we will study topological spin phenomena in mesoscopic systems, such as thin films, heterostructures-interfaces and micron-sized structures from single crystals. We intend to tailor the magnetic spin textures by materials design and the dimensions of the device. We will be exploring novel Heusler and related Mn-based compounds with chiral spin textures. The topological features will be detected through transverse and longitudinal transport measurements at different temperatures and external magnetic and electric fields.The work plan is divided into two parts. In the first part, we will prepare micron-sized structures from hard magnetic phases of PtMnGa, MnBi, Nd2Fe14B, Dy2Fe14B, the chiral compound FePtMo3N and the ferromagnetic van der Waals semimetal Fe3GeTe2. We will detect the topological magnetic excitations through transport measurements. Additionally, the transport responses will be combined with real-space imaging techniques by our collaborators. In the second part, we plan to investigate high-quality epitaxial thin films, heterostructures and interfaces. We will be exploring: (i) New Heusler compounds with D2d symmetry, such as Mn2IrSn and Mn2PtIn, theoretically predicted to host antiskyrmions. The goal is to find a fully compensated ferrimagnet or antiferromagnetic Heusler material with antiferromagnetic skyrmions. (ii) New compounds such as the hexagonal PtMnGa(Al) and MnBi. (iii) The combination of different quantum materials, e.g., topological insulator or semimetal / (anti)skyrmion, ferroelectric / (anti)skyrmion. We aim to grow heterostructures with high quality interfaces where we expect to find novel properties, large spin Hall effect, and new advanced functionalities.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2137: Skyrmionics: Topological Spin Phenomena in Real-Space for Applications
• Co-Investigator: Anastasios Markou, Ph.D.