"We were able to demonstrate a hitherto undiscovered interaction. It occurs between two thin magnetic layers separated by a non-magnetic layer."Kyujoon Lee, Johannes Gutenberg University Mainz
The more we stream videos, download audiobooks and store photos on our mobile devices, the more storage capacity we will need, and so researchers are working to develop new data storage options. One possibility is racetrack memory, where the data is stored in the form of oppositely magnetized areas, or domains, on nanowires.
A research team from Johannes Gutenberg University (JGU) Mainz in Germany, together with colleagues from Eindhoven University of Technology in the Netherlands and from Daegu Gyeongbuk Institute of Science and Technology and Sogang University in South Korea, has now made a discovery that could significantly improve racetrack memory devices.
In the future, the team says, instead of using individual domains in magnetic materials, information could be stored in three-dimensional spin structures, making the memories faster and more robust and providing a larger data capacity. The researchers report their work in a paper in Nature Materials.
"We were able to demonstrate a hitherto undiscovered interaction," explained Kyujoon Lee of JGU Mainz. "It occurs between two thin magnetic layers separated by a non-magnetic layer."
Usually, electron spins align either parallel or antiparallel to each other, as would be expected to occur in separate magnetic layers. However, in this work, the researchers were able to show that in certain systems the spins in the two layers are twisted against each other, aligned perpendicularly at an angle of 90°. This new interlayer coupling interaction was explained through theoretical calculations performed by project partners at the Peter Grünberg Institute (PGI) and the Institute for Advanced Simulation (IAS) at Forschungszentrum Jülich in Germany.
The Mainz-based researchers examined a number of different combinations of materials grown in multi-layers. They were able to show that this previously unknown interaction exists in different systems and can be engineered by the design of the layers. Theoretical calculations allowed them to understand the mechanisms responsible for this novel effect.
With these results, the researchers have revealed a missing component in the interaction between such layers. "These results are very interesting to the scientific community in that they show that the missing antisymmetric element of interlayer interaction exists," said Dong-Soo Han from JGU Mainz. This opens up the possibility of designing various three-dimensional spin structures, which could lead to new magnetic storage units.
"I am very happy that this collaborative work in an international team has opened a new path to three-dimensional structures that could become a key enabler for new 3D devices," said Mathias Kläui from JGU Mainz and senior author of the paper.
This story is adapted from material from Johannes Gutenberg University Mainz, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.