US scientists squeeze exotic crystals, find way to control magnetism in electronics

Key TakeawaysUS researchers discovered that squeezing tiny crystals between two titanium plates can significantly alter their magnetic behavior.The experiments involved two altermagnetic materials, manganese telluride and iron sulfide.Mechanical pressure could offer a simple way to control magnetism and electron flow in future electronic materials. Scientists in the U.S. have found a new way to alter the magnetic behavior of tiny crystals after discovering that squeezing them between two metal plates can change their properties. The experiments were carried out at the Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL) in Tennessee. To test the method, the team examined two materials from an emerging class of magnets known as altermagnets. Altermagnets are a third fundamental class of magnetic materials that combine traits of both ferromagnets and antiferromagnets. They reportedly have zero net magnetization like antiferromagnets, and exhibit strong momentum-dependent spin polarization and band splitting like ferromagnets. Lab tests showed that mechanical pressure could change the materials’ magnetic domains and electron flow. This, according to the team, could allow better control of magnetism in future electronic devices. Pressure alters magnetism For the experiments, the research team used tiny crystals of manganese telluride (MnTe) and iron sulfide (FeS). They then placed the crystals between two titanium plates and applied mechanical pressure. They then examined the materials using neutron diffraction at ORNL’s Spallation Neutron Source (SNS), which produces some of the world’s most intense pulsed neutron beams. The facility uses an accelerator to fire short proton pulses at a liquid mercury target. This releases neutrons that scientists use to study materials and their properties. It revealed how pressure affected the magnetic structure of the crystals. According to ORNL, even a small mechanical squeeze was enough to change the populations of these domains. The researchers also saw changes in an electrical response known as the anomalous Hall effect (AHE) which is associated with the magnetic properties of the materials. The anomalous Hall effect (AHE) occurs when an electric current flows through a magnetic material and creates a voltage across it. Unlike the ordinary Hall effect, it is driven by the material’s internal magnetic properties rather than an external magnetic field. Applications in electronics The results suggest that pressure can provide a simple way to control magnetism and electron flow in altermagnets. The researchers reported them in two separate studies. Feng Ye, PhD, an ORNL neutron scientist and co-author of both studies, stressed the role of neutron scattering in understanding these magnetic changes. “What’s exciting is that one creative experimental idea, a small mechanical squeeze between two plates, can reveal entirely new magnetic behavior and push the field forward,” Ye pointed out in a press release. Ye added that the findings could be particularly important for an emerging field known as spintronics, also known as spin electronics. The field uses the spin of electronics, rather than just their electric charge, to store and process information. The technology could lead to faster, and more energy-efficient electronic devices, such as advanced memory and computing systems. “By controlling the magnetic domains, we can directly influence the transport behavior, and that opens the door to exploring these materials for spintronic technologies,” Pengcheng Dai, PhD, a researcher at Rice University and former neutron scientist at ORNL, said. The findings have been published in the journals Physical Review X and Advanced Materials. Get the latest in engineering, tech, space & science - delivered daily to your inbox.Based in Skopje, North Macedonia. Her work has appeared in Daily Mail, Mirror, Daily Star, Yahoo, NationalWorld, Newsweek, Press Gazette and others. She covers stories on batteries, wind energy, sustainable shipping and new discoveries. When she's not chasing the next big science story, she's traveling, exploring new cultures, or enjoying good food with even better wine.