Researchers have found new properties of very thin magnetic layers – just a few atoms deep – that could lead to better ways to store large amounts of data on smaller devices.
In a study published earlier this month in the journal Nature Communications, researchers described their findings, which add a more detailed understanding of quantum materials and magnetism.
"What we found is a way to measure magnetism at the two-dimensional level, and we found that one particular type of magnet retains its magnetism even at the atomic level," said Rolando Valdes Aguilar, a senior author on the paper and assistant professor of physics at The Ohio State University.
"This is an exciting result for physics, and when we think about how it could play out in the real world, this is a building block."
A lot of science happens kind of like a construction site, with one layer of discoveries building on the next, and as science goes, Valdes Aguilar said, this is a base-layer discovery – meaning it won't change the way data is stored today. But it does give scientists and engineers a starting point from which to build.
At the heart of this study is a class of materials called "van der Waals magnetic materials." These materials have a lot of promise for building better electronics because they maintain magnetic ordering – the characteristic by which spins in atoms order themselves and allow magnets to interact – over long ranges, even in layers that are one atom deep.
That the magnets continue to work even in very thin layers makes them good potential sources for building things like data storage devices, Valdes Aguilar said.
For this study, researchers from Ohio State, the National Institute of Standards and Technology in Maryland and other institutions around the world developed a test to evaluate the spin order of van der Waals magnets. That spin is important – it is the force that deflects electrons, creating a magnetic field at the atomic level. In order for a magnetic material to work properly for the purposes of electronics, different layers must be able to have opposing spins.
"What we found is, when these magnets are very thin, maybe a few atomic layers, the layers actually stack up with one spin up and one spin down, and that arrangement can be controlled with an external magnetic field," Valdes Aguilar said.
The research team on this study hoped to develop a technique to test that spin arrangement – and were successful, using spectroscopy. Spectroscopy works by measuring unique signatures of the atomic structure of materials. The team essentially created a way to examine the spins almost at the atomic level – and that technique could potentially be used to evaluate other magnets at that level, too.
"Since we've demonstrated that this technique can directly probe the arrangement of the spins, we're hoping we can use this for other two-dimensional magnets," Valdes Aguilar said. "This points to a way to make things like jump drives have smaller memories – we can theoretically use this to find a way to increase the memory density of a drive."
Other Ohio State researchers who worked on this study include Thuc T. Mai, Franz G. Utermohlen, Xiaozhou Feng, Dmitry Shcherbakov, ChunNing Jeannie Lau, Yuanming Liu and Nandini Trivedi.
