3D Magnetic Interactions Could Lead to New Forms of Computing

A new form of magnetic interaction that pushes a once-two-dimensional phenomenon into the third dimension could open up a host of exciting new possibilities for data storage and advanced computing, according to scientists.

In a new article published today in the journal Nature's materials, a team led by Glasgow University physicists describe how a new way to successfully transmit information from a series of tiny magnets arranged on an ultra-thin film and the magnets of a second film located below.

Their breakthrough adds an additional dimension, both literal and metaphorical, to "spintronics", the scientific domain dedicated to data storage, retrieval and processing, which has already had a major impact on the technology sector.

Anyone who has ever played with a pair of magnets understands that opposites attract: the south pole of a magnet attracts the north pole of the other. This is true at the scale most people know, but the way magnets interact with each other undergoes significant changes as the magnets contract.

At the nanoscale, where magnetic materials can only represent a few billion meters, magnets interact with each other in a strange and innovative way, including drawing and repelling at a 90 degree angle rather than in upright position.

Scientists have already learned to exploit these unusual properties to encode and process information in thin films coated with a single layer of magnets at the nanoscale.

The advantages of these "spintronic" systems – low power consumption, large storage capacity and greater robustness – have greatly enriched the technology, such as magnetic hard drives, and have earned those who have discovered spintronics a Nobel Prize in 2007.

However, the functionality of magnetic systems used today in computers remains confined to a single plane, which limits their capacity. At present, the team led by the University of Glasgow, in collaboration with partners from the Universities of Cambridge and Hamburg, Technical University Eindhoven and the Faculty of Science at Aalto University, has point a new way to communicate information of a layer with storage potential and calculation.

Dr. Amalio Fernandez-Pacheco, an early career EPSRC researcher at the Faculty of Physics and Astronomy at the University, is the lead author. He said: "The discovery of this new type of interaction between neighboring layers offers us a rich and interesting way to explore and exploit unprecedented 3D magnetic states in multi-scale magnets. at the nanoscale.

"It's a bit like playing an extra note in a musical range. This opens up a whole new world of possibilities, not just for the conventional processing and storage of information, but potentially for new forms of computing that we did not even think about. of again. "

The inter-layer information transmission created by the team is based on what physicists call chiral spin interactions, a type of magnetic force that promotes a particular direction of rotation in neighboring nanoscale magnets. Thanks to recent advances in spintronics, it is now possible to stabilize these interactions within a magnetic layer. This has for example been exploited to create skyrmions, a type of magnetic object at the nanoscale with superior properties for computer applications.

The team's research has now extended these types of interactions to neighboring layers for the first time. They manufactured a multilayer system of ultra-thin magnetic films separated by non-magnetic metal spacers. The structure of the system and precise adjustment of the properties of each layer and its interfaces create unusual inclined magnetic configurations, in which the magnetic field of the two layers form angles between zero and 90 degrees.

Unlike standard multi-layer magnets, it is easier for these magnetic fields to form clockwise configurations than counter-clockwise, a fingerprint indicating that the magnetic fields are in the right direction. an inter-chiral chiral spin interaction exists between the two magnetic layers. This rotational symmetry failure was observed at ambient temperature and under standard environmental conditions. As a result, this new type of magnetic interaction between layers opens interesting perspectives for the realization of topologically complex 3D magnetic configurations in spintronic technologies.

The team's paper, entitled "Dzyaloshinskii-Moriya Interactions Interleaving that Breaks Symmetry in Synthetic Antiferromagnets", is published in Nature's materials.