Researchers at the University of Glasgow, Universities of Cambridge and Hamburg, the Technical University of Eindhoven, and the Aalto University School of Science have uncovered a unique type of magnetic interaction that pushes a two-dimensional event into the third dimension. The researchers believe this interaction could open greater possibilities for data storage and advanced computing. In a paper published in Nature Materials, a team led by physicists from the University of Glasgow describe how they found a way to successfully pass information from a series of tiny magnets arrayed on an ultrathin film across to magnets on a second film below.
Positioning a pair of magnets, opposite poles attract, i.e., the south pole of one magnet attracts the north pole of the other. While that’s true at the scale most people are familiar with, the way magnets interact with each other undergoes some significant changes as magnets shrink.
At the nanoscale, where magnetic materials can be just a few billionths of a meter in size, magnets interact with each other in unique ways, including the possibility of attracting and repelling each other at 90° angles instead of straight-on. Scientists have already learned how to exploit those unusual properties to encode and process information in thin films covered in a single layer of nanoscale magnets.
The functionality of magnetic systems used today in computers remains confined to one plane, limiting their capacity. Now, the University of Glasgow-led team – along with partners from the Universities of Cambridge and Hamburg, the Technical University of Eindhoven and the Aalto University School of Science – have developed a new way to communicate information from one layer to another, adding new potential for storage and computation.
Dr. Amalio Fernandez-Pacheco, an EPSRC Early Career Fellow in the University’s School of Physics and Astronomy, is the lead author on the paper. He said: “The discovery of this new type of interaction between neighbor layers gives us a rich and exciting way to explore and exploit unprecedented 3D magnetic states in multi-layered nanoscale magnets. It’s a bit like being given an extra note in a musical scale to play with - it opens up a whole new world of possibilities, not just for conventional information processing and storage, but potentially for new forms of computing we haven’t even thought of yet.”
The inter-layer transmission of information the team has created relies on what is known to physicists as chiral spin interactions, a type of magnetic force that favors a sense of rotation in neighbor nanoscale magnets. Thanks to recent advances in spintronics, it is now possible to stabilize these interactions within a magnetic layer. This has for instance been exploited to create skyrmions, a type of nanoscale magnetic object with superior properties for computing applications.
The team’s research has now extended these types of interactions to neighboring layers for the first time. They fabricated a multi-layered system formed by ultra-thin magnetic films separated by non-magnetic metallic spacers. The structure of the system, and a precise tuning of the properties of each layer and its interfaces, creates unusual canted magnetic configurations, where the magnetic field of the two layers forms angles between zero and 90 degrees.
Unlike standard multi-layered magnets, it becomes easier for these magnetic fields to form clockwise configurations than anticlockwise ones, a fingerprint that an interlayer chiral spin interaction exists in between the two magnetic layers. This breaking of rotational symmetry was observed at room temperature and under standard environmental conditions.
As a result, this new type of interlayer magnetic interaction opens exciting perspectives to realize topologically complex magnetic 3D configurations in spintronic technologies. Learn more by reading the team’s paper, titled “Symmetry-Breaking Interlayer Dzyaloshinskii-Moriya Interactions in Synthetic Antiferromagnets” in Nature Materials.