Periodic Reporting for period 2 - SKDWONTRACK (Room temperature stabilization and all-electrical manipulation of chiral spin structures in metallic multilayers)
Berichtszeitraum: 2020-01-01 bis 2020-12-31
On the one hand, the development of new systems with embedded intelligence and sensing devices (like in autonomous driving cars) will generate a massive increase in computation. This will not be feasible at current levels of devices’ power consumption, which calls for the design of more energy efficient technologies. While semiconductor microelectronics has reached its intrinsic limitations, spintronics offers a new path towards the design of memory and logic devices with high density and low power consumption. However, present spintronic devices such as magnetic-RAMs still suffer from high current density requirements. These drawbacks call for the development of new magnetic materials systems with intrinsically stable magnetic states, easy to manipulate and detect at a low energy cost. Metallic multilayers hosting non-collinear spin-structures such as magnetic skyrmions offer a highly promising solution. Their topological stability and outstanding transport properties make them a natural choice for the development of new memory and logic devices.
On the other hand, in the last 15 years quantum computing moved from being a mere theoretical subject to a more applied one. Currently, there is a large interest in the discovery and development of new quantum materials which can be employed in the design of quantum computers. Non-collinear magnetic systems (e.g. skyrmionic systems) can play an important role in the development of new quantum materials. Indeed, the combination of superconducting materials and non-collinear magnetic systems can give access to what is called topological superconductivity, which is very interesting for the development of quantum computing systems.
The main objective of the project was the design, investigation and engineering of new metallic multilayers hosting non-collinear and topologically protected magnetic states. Several different materials systems hosting non-collinear magnetism have been developed and studied. One main achievement of the action was the stabilization and the tuning of room-temperature magnetic skyrmions in the absence of any external magnetic field. This is key to the design of skyrmion-based electronic devices which are compatible with the miniaturization requirements of nanoelectronics.
Furthermore, the project also focused on the understanding of new ways to stabilize non-collinear magnetism in thin film systems. Until now, due to the requirement of large spin-orbit coupling (SOC) for the stabilization of non-collinear spin-textures, [heavy metals]\magnet heterostructures have represented the main platform for this kind of studies. Accordingly, the interest was in going beyond the [heavy metal]\magnet platform and discover new mechanisms to stabilize non-collinear magnetism. In this direction goes the exploration and demonstration of the stabilization of non-collinear spin-textures in a multilayer system via Oxygen chemisorption (G. Chen, R. Lo Conte et al., Science Advances 6 : eaba4924 (2020)). This surprising effect is understood as the result of the presence of a large Rashba-SOC at the Oxygen/magnet interface, which opens up a complete new avenue for the stabilization of topologically non-trivial magnetic states in thin-film magnetic systems.
All the scientific results obtained in this project have contributed to better understand the origin of non-collinear, topological spin-textures in magnetic thin film multilayers, allowing to make one more step towards the design of novel solid state magnetic memory and logic devices based on topologically protected spin-states.
In order to maximize the impact of this action among the scientific community, the scientific results described above have been/will be presented at several national and international seminars and conferences:
1. APS March Meeting 2021 (virtual), March 2021 (invited)
2. Joint European Magnetic Symposia (JEMS) 2020 Virtual Conference, Dec 2020
3. Virtual Conference on Magnetism and Magnetic Materials 2020, Nov 2020
4. Imaging Facility Seminar, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley-CA, USA, Dec 10, 2019 (invited)
In addition to the possible application of skyrmions in spintronic devices, topological magnetic spin-textures can also be employed in the making of new quantum materials systems. Indeed, joining non-collinear magnetism (e.g. skyrmions) and superconductors can give access to topological superconductivity, which can be applied in topological quantum computing. Accordingly, the development of a platform where magnetic skymions can be stabilized without any external magnetic field offers a new way towards the design of quantum technologies.