Frustrated magnetic skyrmions and antiskyrmions could enable novel spintronic applications

November 27, 2017, The Chinese University of Hong Kong, Shenzhen
Skyrmions and antiskyrmions with different topological numbers in a frustrated magnet. Credit: Xichao Zhang

The 2016 Nobel Prize in Physics was awarded to three theoretical physicists for their discoveries of topological phase transitions and topological phases of matter, which highlights the role and significance of topology in understanding the physical world. In the field of magnetism, topology is also directly related and fundamental to the physics of an exotic magnetic texture, the magnetic skyrmion.

Magnetic skyrmions are nanoscale magnetic structures with topological quantum numbers, which exist in a number of materials and can be controlled by methods such as electric current and others. Due to their nanoscale size and topologically protected stability, hold great promise in spintronic applications such as magnetic memory and logic computing devices. In order to manipulate magnetic skyrmions for information processing, it is essential to fully understand their dynamics.

Recently, a team of researchers from China and Japan has studied the magnetic skyrmions in frustrated magnets and revelled the exotic dynamics of frustrated magnetic skyrmions, which is totally different from that of magnetic skyrmions in common ferromagnetic materials. They found the helicity locking-unlocking transition of frustrated magnetic skyrmions by including dipole-dipole interactions in their theoretical model, which is an energy term usually negligible for common ferromagnetic skyrmions. In the frustrated magnets, the dipole-dipole interaction plays an important role in the helicity (rotational mode)-orbit (translational mode) coupling of the skyrmion, especially at low temperature. In addition, the researchers show that the current-controlled skyrmions and antiskyrmions dynamics with locking-unlocking helicity in frustrated magnets can enable novel spintronic applications such as the helicity-based information storage devices.

The discovery are reported this week in the journal Nature Communications, in a paper by the Chinese University of Hong Kong, Shenzhen researcher Xichao Zhang, and PhD student Jing Xia, and four others from Shenzhen University, China, Shinshu University, Japan, and the University of Tokyo, Japan.

"Helicity is a degree of freedom of frustrated magnetic skyrmions," says Xichao Zhang, a researcher at the Chinese University of Hong Kong, Shenzhen, and the first author of the study. "In conventional ferromagnetic materials, the helicity of a skyrmion cannot be effectively controlled, while we find it is possible to control the helicity by utilizing the helicity locking-unlocking transition in frustrated magnetic materials." Zhang adds that the control of helicity can lead to novel spintronic applications such as the helicity-based skyrmionic memories.

"Our study also shows the interactions between frustrated skyrmions and antiskyrmions, which are problems of both theoretical and practical significance," explains Yan Zhou, associate professor of the Chinese University of Hong Kong, Shenzhen, and the corresponding author of the study. Zhou says it is also possible to build logic computing devices based on skyrmions and antiskyrmions, and his group is pursuing this currently.

"We can use frustrated skyrmions as a binary memory utilizing two stable Bloch-type states, where the helicity can be switched by applying current," says Motohiko Ezawa, lecturer of the University of Tokyo, and the other corresponding author of the study.

Explore further: Frustrated magnets point towards new memory

More information: Zhang, X. et al. Skyrmion dynamics in a frustrated ferromagnetic film and current-induced helicity locking-unlocking transition, Nature Communications 8, 1717 (2017). DOI: 10.1038/s41467-017-01785-w

Related Stories

Frustrated magnets point towards new memory

September 23, 2015

Theoretical physicists from the University of Groningen, supported by the FOM Foundation, have discovered that so-called 'frustrated magnets' can produce skyrmions, tiny magnetic vortices that may be used in memory storage. ...

Unlocking the potential of magnetic skyrmions

November 2, 2017

Magnetic skyrmions offer the promise of next-generation memory and computing technologies, such as cache memory devices and cloud computing. Now A*STAR researchers have developed an innovative technique for making tunable ...

Recommended for you

How bacterial communities transport nutrients

December 12, 2018

Under threat of being scrubbed away with disinfectant, individual bacteria can improve their odds of survival by joining together to form colonies, called biofilms. What Arnold Mathijssen, postdoctoral fellow in bioengineering ...

New method gives microscope a boost in resolution

December 12, 2018

Scientists at the University of Würzburg have been able to boost current super-resolution microscopy by a novel tweak. They coated the glass cover slip as part of the sample carrier with tailor-made biocompatible nanosheets ...

Copper compound as promising quantum computing unit

December 12, 2018

Quantum computers could vastly increase the capabilities of IT systems, bringing major changes worldwide. However, there is still a long way to go before such a device can actually be constructed, because it has not yet ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.