Scientists at the U.S. Department of Energy’s Oak Ridge National Laboratory (ORNL) have found that modest mechanical pressure can substantially alter the magnetic properties of a promising class of materials known as alternating magnets. Neutron experiments showed that compressing crystals of manganese telluride and iron sulfide changes their magnetic domains and electrical behavior, suggesting a simple way to control materials being investigated for future electronic technologies.
Why alternating magnets matter for future electronics
The findings were reported in two consecutive studies published in 2016 in Physical Review X and Advanced Materials. Together, the studies show that mechanical strain can influence both a material’s magnetic structure and the movement of its electrons.
One potential application is spintronics, or spin electronics. Unlike conventional electronics, which processes and stores information using the electrical charge of electrons, spintronics also uses a property known as electron spin.
If researchers can identify and develop suitable materials containing alternating magnets, the approach could contribute to advances in technologies ranging from wireless communications to quantum computing.
“By controlling the magnetic domains, we can directly influence the transport behavior, which opens the door to exploring these materials for spintronics technology,” said Rice University’s Pengcheng Dai, who was a neutron scientist at ORNL.
Mechanical compression changes magnetic behavior
To study how pressure affects the materials, the ORNL team placed small crystals of manganese telluride and iron sulfide between two titanium plates and slowly compressed them.
Using neutron diffraction at ORNL’s Spallation Neutron Source, the scientists examined the magnetic structures inside the crystals. They found that pressure changed the relative abundance of magnetic domains—regions of a material with specific magnetic configurations.
The applied strain also altered the anomalous Hall effect, an electrical phenomenon associated with magnetism. This provided evidence that mechanical compression changed the materials’ electrical behavior as well as their magnetic structure.
“What’s interesting is that one creative experimental idea—a small mechanical squeeze between two plates—can reveal entirely new magnetic behavior and advance the magnetic field. Neutron scattering plays a very important role in revealing fundamental changes in magnetism,” said Feng Ye, a neutron scientist at ORNL and co-author of both publications.
The results demonstrate a relatively simple way to manipulate magnetic materials and could help researchers develop building blocks for future spintronic devices.
ORNL’s Spallation Neutron Source is a DOE Office of Science user facility.
Source: www.sciencedaily.com
