Physicists at Bielefeld University have found a way to reduce waste from heat emitted by electronic devices such as computers. They apply the heat to generate magnetic signals known as spin currents, which has the potential to replace some of the electrical currents in electronic components. The research focuses on testing which materials can generate the most efficient spin current from heat.
In a new study, physicists tested the strength of spin currents for various combinations of thin films. To do this, they took two nanofilms and placed a layer of metal oxide between them, only a few atoms thick. The team heated up one of the external films with a hot nanowire, causing, electrons with a specific spin orientation to pass through the metal oxide to generate the spin current. Alexander Böhnke and Torsten Hübner together with their colleagues Timo Kuschel and Andy Thomas tested different combinations of ultra-thin films by heating one of the external films the same way each time. The experiments yielded magnetic nanostructures, with combinations made of cobalt, iron, silicon and aluminum the most productive. Their findings were published in Nature Communications.
‘“Depending on which material we used, the strength of the spin current varied markedly,” says Böhnke. “That is because of the electronic structure of the materials we used.”’
Thomas started his research on spin caloritronics at Bielefeld University and will continue at the Leibniz Institute for Solid State and Materials Research in Dresden.
Photo: In experiments, including those at The University of Greifswald, researchers are testing which material can generate spin current most effectively. Credit: University of Greifswald