A research team from the Technical University of Kaiserslautern (TUK) has been awarded a Consolidator Grant from the European Research Council (ERC) to develop spintronic devices.
Professor Dr. Mathias Weiler, lead of the study, will receive €2 million over the next five years. Scientists are working on spin waves and new spintronic devices that could drastically accelerate the storage, processing, and transmission of information.
An common issue in spintronics research is the control of magnetic materials with complex spin order. With the funding, Weiler will set out to employ surface acoustic waves to circumvent this problem, which have so far been utilized primarily in smartphones.
When processing information, the electrical charge of electrons is primarily utilized. However, over time, devices are becoming smaller and much more powerful. Thus, an electric current with its high waste heat is reaching its limits, which is why scientists are working on alternatives, such as utilizing spin waves.
“Spin describes the intrinsic angular momentum of a quantum particle, for example an electron or neutron,” explained Professor Dr Mathias Weiler, lead researcher on applied spin phenomena at TU Kaiserslautern. “It forms the basis for all magnetic phenomena.”
Collective excitations of spins – or spin waves – can transport more information than electrons while consuming significantly less energy and generating less waste heat. This makes the possibilities for spin wave applications both interesting and promising. They could be used to develop new spintronic devices that significantly accelerate the processing and storage of information.
An important role is played by magnetic materials that have complex spin orders and associated special properties. Such complex spin orders are found in antiferromagnets and magnetic skyrmions.
“Unlike ferromagnets, which have wide technological applications as permanent magnets, complex magnetic materials cannot be characterized by an easily controllable macroscopic magnetisation,” said Weiler. “Instead, their complex spin structure is protected by quantum mechanical exchange interaction and topology, so it cannot be easily perturbed by external magnetic fields.”
This protection, along with natural frequencies that can reach the terahertz range, makes complex spin systems particularly suitable for robust and fast information processing.
Currently, no efficient methods exist to control spin waves in these systems, therefore the potential of this class of materials remains largely unexplored. This is where the EU-funded project known as ‘Magneto-Acoustic Waves in Complex Spin Systems’ (MAWiCS) comes in.
The researchers aim to combine complex spin systems with surface acoustic waves (SAW), Weiler explained: “Surface acoustic waves are widely used in communication technology. They are used, for example, to realize the numerous frequency filters in smartphones. We will link this current key technology with next-generation spin-based information technology.”
The physicists intend to take advantage of the fact that SAW couples very well with these complex spin systems, which means that they can control them very efficiently. Scientists thereby benefit from their long-standing expertise in utilizing SAW to control ferromagnetic systems, and the team will now extend this expertise to antiferromagnets and chiral magnets.
“With our experiments, we want to lay the groundwork for these materials to come into use in information processing,” Weiler concluded. “They can enable a new class of information technology.”
The work will take place in the new research building, Laboratory for Advanced Spin Engineering (LASE), on TUK’s campus. This scientific research is integrated into the Rhineland-Palatinate-funded state research center, Optics and Materials Sciences (OPRIMAS), which is the TopDyn research initiative.