New materials and interface effects in charge and spin transport in magnetic heterostructures

Günter Reiss, University of Bielefeld

Magnetic heterostructures are key devices for spinelectronics. Their preparation requires a combination of thin film deposition with sub-Å control, field-annealing and nanopatterning. If fully functional, they can help fundamental research on new materials and effects as well open applications in sensors, memories, logic and oscillators. An introduction will present examples for basic effects and their applications.
We then will discuss several novel materials and interface induced effects occurring in magnetic heterostructures:
- The growth of altermagnetic thin films and their integration in magnetic tunnel junctions using the example of RuO2. Such altermagnets are at present intensively investigated due to their potentially spin split band structure and related spin currents. The X-ray analysis reveals a high crystalline quality of the films with or without twinning depending on the choice of the substrate. When integrated with an MgO tunnel barrier and a ferromagnetic counter electrode, signatures of a tunneling magnetoresistance can be found that strongly depend on the bias voltage and are not yet fully understood. When integrated with ferromagnets (Ni80Fe20) or heavy metals (Pt), an analysis based on the 2ω method shows the presence of torques in accordance with a spin current at the interface.
- When replacing the alter- by a ferromagnet, the heavy metal can show a proximity induced ferro-magnetism at the interface that substantially influences the results of well-known phenomena such as the spin Seebeck, anomalous Nernst or anomalous Hall effect. Examples will be discussed using metallic as well as insulating ferro- or ferrimagnets and recipes for disentangling the zoo of effects will be given.

Please sign up here in order to get the Zoom link and regular announcements of the upcoming talks.