Researchers announce spintronics breakthrough
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Researchers have reported the first demonstration of a spintronic device based on an antiferromagnetic. Described as a 'breakthrough' discovery in the field of spintronics, the researchers claim it could strongly influence fundamental research in condensed matter physics systems.
The discovery has been made by a team from Hitachi laboratories in Cambridge and Japan, in collaboration with groups at the Academy of Sciences and Charles University in the Czech Republic. Spin is essential in electronic memory and storage devices, such as components in hard drives or magnetic RAM which use ferromagnetics.
Until now, scientists have been unable to find a physical principle that would enable a spintronic device to operate with an active magnetic electrode made of an antiferromagnetic. These materials have only played a static supporting role in current microelectronics and are often used to enhance the magnetic hardness of ferromagnets via the exchange bias effect.
The group of scientists claims to have introduced not only the principle, but have also developed an experimental realisation of such a spintronics device. They have used a tunnel junction, a sandwich of magnetic electrodes with an insulator in the middle, in which one of the electrodes is an antiferromagnet and the other a non-magnet.
When rotating the spins in the antiferromagnetic electrode, the researchers observed a large change in the tunnel resistance of the studied device, comparable to resistance changes in conventional ferromagnetic spintronic devices. The effect is based on a quantum relativistic phenomenon which, besides its potential for applications, could also strongly influence fundamental research in condensed matter physics systems. The work also presents an efficient manipulation of spin direction in an antiferromagnet, using the exchange spring and provides a means to study magnetic characteristics of antiferromagnets by an electronic transport measurement.
Dr Byong-Guk Park, pictured, a research scientist from the Hitachi Cambridge Laboratory, said: "For spintronics research and its potential applications in sensors or computer microdevices, a new area of antiferromagnetic materials with metal or semiconductor properties has emerged, which is much wider and richer than metal ferromagnets used in spintronic devices to date."
