Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Curved kick on the nanoscale: Investigations of the skyrmion Hall effect reveal surprising results

27.12.2016

One step further towards the application of skyrmions in spintronic devices

Researchers at Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) have made another important breakthrough in the field of future magnetic storage devices. Already in March 2016, the international team investigated structures, which could serve as magnetic shift register or racetrack memory devices. This type of storage promises low access times, high information density, and low energy consumption. Now, the research team achieved the billion-fold reproducible motion of special magnetic textures, so-called skyrmions, between different positions, which is exactly the process needed in magnetic shift registers thereby taking a critical step towards the application of skyrmions in devices. The work was published in the research journal Nature Physics.


The magnetic structure of a skyrmion is symmetrical around its core; arrows indicate the direction of spins.

ill./©: Benjamin Krüger, JGU

The experiments were carried out in specially designed thin film structures, i.e., vertically asymmetric multilayer devices exhibiting broken inversion symmetry and thus stabilizing special spin structures called skyrmions. Those structures are similar to a hair whorl and like these are relatively difficult to destroy. This grants them unique stability, which is another argument for the application of skyrmions in such spintronic devices.

Since skyrmions can be shifted by electrical currents and feel a repulsive force from the edges of the magnetic track as well as from single defects in the wire, they can move relatively undisturbed through the track. This is a highly desired property for racetrack devices, which are supposed to consist of static read- and write-heads, while the magnetic bits are shifted in the track. However, it is another important aspect of skyrmion dynamics that the skyrmions do not only move parallel to the applied current, but also perpendicular to it. This leads to an angle between the skyrmion direction of motion and the current flow called the skyrmion Hall angle, which can be predicted theoretically. As a result, the skyrmions should move under this constant angle until they start getting repelled by the edge of the material and then keep a constant distance to it.

Within their latest research project, scientists of JGU and MIT now proved that the billion-fold reproducible displacement of skyrmions is indeed possible and can be achieved with high velocities. Furthermore, the skyrmion Hall angle was investigated in detail. Surprisingly, it turned out to be dependent on the velocity of the skyrmions, which means that the components of the motion parallel and perpendicular to the current flow do not scale equally with the velocity of the skyrmions. This is not predicted in the conventional theoretical description of skyrmions. Part of the solution of this unexpected behavior could be the deformation of the skyrmion spin structure, calling for more theoretical effort to fully understand the properties of skyrmions.

"I am glad that the collaboration between Mainz University and MIT has already yielded the second high-ranked publication. Considering especially the short time since the collaboration started, this is exceptional and I am happy to be able to participate in it," said Kai Litzius, first-author of the Nature Physics article. Litzius is a scholar of the Graduate School of Excellence "Materials Science in Mainz" (MAINZ) and a member of the team headed by Professor Mathias Kläui.

"In highly competitive fields of research such as that on skyrmions, international cooperation with leading groups is a strategical advantage. Within only two years after the start of the collaboration with our colleagues from MIT, we have already published the second time together in a high-ranked Nature group journal. The MAINZ Graduate School of Excellence facilitates research stays of PhD students from the United States in Mainz and vice versa and therefore contributes significantly to international education and successful research in this field,” emphasized Professor Mathias Kläui of the JGU Institute of Physics, who is also Director of MAINZ.

Establishment of the MAINZ Graduate School was granted through the Excellence Initiative by the German Federal and State Governments to Promote Science and Research at German Universities in 2007 and its funding was extended in the second round in 2012. It consists of work groups from Johannes Gutenberg University Mainz, TU Kaiserslautern, and the Max Planck Institute for Polymer Research in Mainz. One of its focal research areas is spintronics, where cooperation with leading international partners plays an important role.

Publication:
Kai Litzius et al.
Skyrmion Hall effect revealed by direct time-resolved X-ray microscopy
Nature Physics, 26 December 2016
DOI: 10.1038/nphys4000


Further information:
Professor Dr. Mathias Kläui
Condensed Matter Theory Group
Institute of Physics
Johannes Gutenberg University Mainz
55099 Mainz, GERMANY
phone +49 6131 39-23633
e-mail: klaeui@uni-mainz.de
http://www.klaeui-lab.physik.uni-mainz.de

Graduate School of Excellence "Materials Science in Mainz" (MAINZ)
Johannes Gutenberg University Mainz
55099 Mainz, GERMANY
phone +49 6131 39-26984
fax +49 6131 39-26983
e-mail: mainz@uni-mainz.de
http://www.mainz.uni-mainz.de/

Weitere Informationen:

http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys4000.html – Abstract ;
http://www.uni-mainz.de/presse/20165_ENG_HTML.php – press release “International research team achieves controlled movement of skyrmions” (7 March 2016) ;
http://www.uni-mainz.de/presse/18027_ENG_HTML.php – press release “Physicists observe motion of tiny magnetic whirls” (3 March 2015)

Petra Giegerich | idw - Informationsdienst Wissenschaft

More articles from Physics and Astronomy:

nachricht NASA's James Webb Space Telescope completes final cryogenic testing
21.11.2017 | NASA/Goddard Space Flight Center

nachricht Previous evidence of water on mars now identified as grainflows
21.11.2017 | US Geological Survey

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>