A team of researchers from the Department of Physics at Hamburg University, together with col-leagues from the Radboud university in Nijmegen, the FZ Jülich and the MPI of Solid State Research in Stuttgart, explored the atomistic origin of magnetization handedness in a structure containing as few as two iron atoms on a platinum crystal surface and they were able to controllably switch the magnetization of the iron pair back and forth from left-handed to right-handed. This unprecedented control of the magnetization might enable a future design of stable magnetic swirls, so-called skyrmions, with tailored sizes and handedness, which are being discussed as new units for information storage.
Handedness is a peculiar breaking of symmetry where a mirror image of a structure or pattern is different from its original. While the most well-known example is our own hand, which gave the name to this kind of asymmetry, there are many other materials or structures known from different disciplines of natural sciences which show handedness: Amino acids and sugars, snail shells, and swirls of the magnetization, so called skyrmions, which have recently been heavily investigated because of their promise as new units for the storage of bits in information technology.
The Figure shows a pair of magnetic iron atoms on top of a platinum crystal surface as “seen” with a scanning tunneling microscope (hillocks). The spectra of the left and right atom (green and red lines), taken with the same microscope, show characteristic gaps, that tell the scientists a clockwise rotation of the atoms’ magnetization exists, as illustrated by the clockwise rotation of the arrows from the green to the red sphere representing the iron atoms. The reason for this right-handedness is a peculiar magnetic handshake mediated by the platinum atoms in the substrate (blue spheres) below the iron pair which breaks the mirror symmetry, as apparent from the mirror image on the bottom.
University of Hamburg
In all of these structures, we can differentiate righties and lefties, which are mirror images of each other. While in some of these examples lefties and righties are almost equally represented in nature, in many others one sort of handedness is dominating. Scientists have since wondered about the possible origin of this so called homo-chirality, and it has been even proposed that evolutionary processes are responsible for handedness in some systems.
The Hamburg research team has now explored the source of magnetic handedness in the smallest possible units. By observing a pair of iron atoms, which are lying on a platinum crystal, with a scanning tunneling microscope (see Figure) they were able to deduce a clockwise rotation of the magnetization, i.e. the pair is right-handed.
Moreover, moving the right atom by only one atomic diameter farther apart from the left atom changes the rotation of the magnetization from clockwise to anti-clockwise, i.e. the pair gets left-handed. Together with the theory group of the Forschungszentrum Jülich, the team was able to show that the mechanism responsible for this handedness is a magnetic handshake between the two atoms mediated by the platinum substrate atoms (see the Figure).
The researchers now hope that they can use the tip of the scanning tunneling microscope as a tool in order to build lattices of hundreds of such iron atoms, which might then host left- or right-handed skyrmions.
Tailoring the chiral magnetic interaction between two individual atoms
A. A. Khajetoorians, M. Steinbrecher, M. Ternes, M. Bouhassoune, M. dos Santos Dias, S. Lounis,
J. Wiebe, and R. Wiesendanger,
Nature Communications 7, 10620 (2016).
Jungiusstr. 9A, 20355 Hamburg
Tel.: (0 40) 4 28 38 - 69 59
Fax: (0 40) 4 28 38 - 24 09
Heiko Fuchs | idw - Informationsdienst Wissenschaft
Next Generation Cryptography
20.03.2018 | Fraunhofer-Institut für Sichere Informationstechnologie SIT
TIB’s Visual Analytics Research Group to develop methods for person detection and visualisation
19.03.2018 | Technische Informationsbibliothek (TIB)
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
22.03.2018 | Trade Fair News
22.03.2018 | Earth Sciences
22.03.2018 | Earth Sciences