Physicists of the University of Hamburg, Germany, managed for the first time to individually write and delete single skyrmions, a knot-like magnetic entity. Such vortex-shaped magnetic structures exhibit unique properties which make them promising candidates for future data storage devices.
Figure 1: A skyrmion can be imagined as a two-dimensional magnetic knot, in which the magnetic moments are rotating with unique rotational sense by 360° within a plane. The image shows data from a spin-resolved scanning tunneling microscopy experiment together with a sketch of the sample magnetization.
Group of R. Wiesendanger, University of Hamburg
Skyrmions have been in the focus of active research for the last years; however, up to now these states have been merely investigated, a controlled manipulation has not been achieved. Now this has been realized by scientists from the group of Prof. Roland Wiesendanger in Hamburg, Germany: as Science Magazine reports online on 08th of August 2013, the creation and annihilation of single skyrmions, corresponding to writing and deleting of information on a storage medium, has been demonstrated by these researchers.
This work solves one of the longstanding technical problems concerning the future use of skyrmions in information technology.
Using more “robust” magnetic structures like skyrmions could be a way out of this technological dead end. These structures can be imagined as a two-dimensional knot in which the magnetic moments are rotating about 360° in a plane with a unique rotational sense (see Fig. 1). These particle-like magnetic knots can be assigned a kind of charge, the topological charge. With this it is possible to assign the bit states “1” and “0” to the existence or non-existence of a skyrmion.
A clever choice of temperature and external magnetic field enabled the scientists of the group of Prof. Roland Wiesendanger to prepare and manipulate single magnetic skyrmions for the first time. They used a two atomic layer thick film of palladium and iron on an iridium crystal. In an external magnetic field this sample exhibits single localized skyrmions with a diameter of a few nanometers that can be imaged in a spin-polarized scanning tunneling microscope. Using small currents from the tip of the microscope these skyrmions can be written and deleted. For the creation the previously parallel magnetic moments are twisted to form a knot-like magnetic state, and for the deletion this knot is unwound again.
„We finally found a magnetic system in which we can locally switch between ordinary ferromagnetic order and a complex spin configuration“, says Dr. Kirsten von Bergmann, senior scientist in the Wiesendanger group. As published in the current issue of the Science Magazine, four skyrmions were specifically addressed and could be created and annihilated (Fig. 1). “We transferred the idea of tying a knot to memorize something to the field of storage technology so we can now store data in a two-dimensional magnetic knot”, explains Ph.D. student Niklas Romming.
Whether skyrmions will be used as data storage units in our computers, tablets, or smartphones, is not foreseeable. The experimentally accomplished writing and deleting of skyrmions, however, has demonstrated the feasibility of this technology and paved the way towards a realization of such devices.Original publication:
Science (2013).Further questions:
Sharpening the X-ray view of the nanocosm
23.03.2018 | Changchun Institute of Optics, Fine Mechanics and Physics
Drug or duplicate?
23.03.2018 | Fraunhofer-Institut für Angewandte Festkörperphysik IAF
Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.
The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...
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...
23.03.2018 | Event News
19.03.2018 | Event News
16.03.2018 | Event News
23.03.2018 | Materials Sciences
23.03.2018 | Agricultural and Forestry Science
23.03.2018 | Physics and Astronomy