Researchers from Daegu Gyeongbuk Institute of Science and Technology (DGIST) in Korea have demonstrated a novel route to tune and control the magnetic domain wall motions employing combinations of useful magnetic effects inside very thin film materials. The research offers a new insight into spintronics and a step towards new ultrafast, ultrasmall, and power-efficient IT devices.
The new study demonstrates a new way to handle information processing using the movement of the magnetic states of the thin film device. It takes advantage of some unusual effects that occur when materials with contrasting types of magnetic material are squashed together. The research focuses on a device that combines ferromagnetic and antiferromagnetic materials, in which the directions of electron spins align differently within the respective magnetic materials.
Much research in spintronics focuses on the narrow region where two such contrasting magnetic materials meet, and how this 'domain' and 'domain wall' can propagate. An external electric current, for example, can shift the magnetic domain, although this process is hard to control and does not offer a precise enough movement as yet that scientists seek.
Jung-Il Hong of the Department of Emerging Materials Science at DGIST and his colleagues take advantage of another 'effective' magnetic field that was already present in the system combining the DMI and exchange bias effects. Spins line up in different ways in response to the magnetic field and electrical currents in the magnetic structure, and the behavior of magnetic domains could also be controlled due to those combined magnetic effects.
They also demonstrate that the direction of the exchange bias field can be reconfigured by simply injecting spin currents through the device, enabling electrical and programmable operations of the device.
Hong says that "in order for spintronics devices to go from theory to reality, the behaviors of magnetic domains and the domain wall interfaces that separate them need to be understood properly in multi-layered materials. Our work takes a step towards a finer operation of domain manipulation in the device structure that we believe could easily be integrated in logic devices."