Researchers from Johannes Gutenberg University Mainz demonstrate a new principle for magnetic recording / Publication in Nature Nanotechnology
The research group of Professor Jairo Sinova at the Institute of Physics at Johannes Gutenberg University Mainz (JGU), in collaboration with researchers from Prague, Cambridge, and Nottingham, have predicted and discovered a new physical phenomenon that allows to manipulate the state of a magnet by electric signals. Current technologies for writing, storing, and reading information are either charge-based or spin-based.
Semiconductor flash or random access memories are prime examples among the large variety of charge-based devices. They utilize the possibility offered by semiconductors to easily electrically manipulate and detect their electronic charge states representing the "zeros" and "ones". The downside is that weak perturbations such as impurities, temperature change, or radiation can lead to uncontrolled charge redistributions and, as a consequence, to data loss. Spin-based devices operate on an entirely distinct principle.
In some materials, like iron, electron spins generate magnetism and the position of the north and south pole of the magnet can be used to store the zeros and ones. This technology is behind memory applications ranging from kilobyte magnetic stripe cards to terabyte computer hard disks. Since they are based on spin, the devices are much more robust against charge perturbations. However, the drawback of current magnetic memories is that in order to reverse the north and south poles of the magnet, i.e., flip the zero to one or vice versa, the magnetic bit has to be coupled to an electro-magnet or to another permanent magnet. If instead one could flip the poles by an electric signal without involving another magnet, a new generation of memories can be envisaged combining the merits of both charge and spin-based devices.
In order the shake a magnet electrically without involving an electro-magnet or another permanent magnet one has to step out of the realm of classical physics and enter the relativistic quantum mechanics. Einstein’s relativity allows electrons subject to electric current to order their spins so they become magnetic. The researchers took a permanent magnet GaMnAs and by applying an electric current inside the permanent magnet they created a new internal magnetic cloud, which was able to manipulate the surrounding permanent magnet. The work has been published in the journal Nature Nanotechnology on 2 March 2014.
The observed phenomenon is closely related to the relativistic intrinsic spin Hall effect which Jörg Wunderlich, Jairo Sinova, and Tomas Jungwirth discovered in 2004 following a prediction of Sinova and co-workers in 2003. Since then it has become a text-book demonstration of how electric currents can magnetize any material. "Ten years ago we predicted and discovered how electric currents can generate pure spin-currents through the intrinsic structure of materials. Now we have shown how this effect can be reversed to manipulate magnets by the current-induced polarization.
These new phenomena are a major topic of research today since they can lead to new generation of memory devices. Besides our on-going collaborations, this research direction couples very well with on-going experimental research here in Mainz. Being part of this world-leading research and working with superb colleagues is an immense privilege and I am very excited about the future", says Professor Jairo Sinova.
Kurebayashi, H., Sinova, J. et al.
An antidumping spin–orbit torque originating from the Berry curvature
Nature Nanotechnology, 2 March 2014
Electrically shaken GaMnAs magnet
(source/©: Jairo Sinova)
Professor Dr. Jairo Sinova
Institute of Physics
Johannes Gutenberg University Mainz (JGU)
D 55099 Mainz, GERMANY
phone +49 6131 39-21284
http://dx.doi.org/10.1038/nnano.2014.15 - Article in NATURE NANOTECHNOLOGY ;
http://www.uni-mainz.de/presse/17107_ENG_HTML.php - press release ;
http://www.sinova-group.physik.uni-mainz.de/ - Sinova Group at the JGU Institute of Physics
Petra Giegerich | idw - Informationsdienst Wissenschaft
Researchers use light to remotely control curvature of plastics
23.03.2017 | North Carolina State University
TU Graz researchers show that enzyme function inhibits battery ageing
21.03.2017 | Technische Universität Graz
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy