Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Simple detection of magnetic skyrmions

06.10.2015

New physical effect: researchers discover a change of electrical resistance in magnetic whirls

At present, tiny magnetic whirls – so called skyrmions – are discussed as promising candidates for bits in future robust and compact data storage devices. At the University of Hamburg these exotic magnetic structures were recently found to exist in ultrathin magnetic layers and multilayers, similar to the ones used in current hard-disk drives and magnetic sensors.


Figure: Magnetic whirls with a diameter of only a few nanometers occur in a thin film of palladium and iron (bottom, cones represent single atoms of the surface and they point into the direction of the atomic magnets). The resistance, measured with a metallic probe close to the surface changes inside the skyrmion as compared to its surrounding (top, experimental data across a skyrmion, see original publication). The change in resistance is continuous and becomes strongest, when the canting between neighboring atomic magnets is largest, in this case in the skyrmion center.

(Image: C. Hanneken, University of Hamburg)

However, up to now an additional magnet was necessary for a read-out of skyrmions. Now researchers from the University of Hamburg and the Christian-Albrechts-Universität in Kiel have demonstrated that skyrmions can be detected much more easily because of a drastic change of the electrical resistance in these magnetic whirls. For future data storage concepts this promises a significant simplification in terms of fabrication and operation.

Stable whirls in magnetic materials (see figure) were predicted over 25 years ago, but the experimental realization was achieved only recently. The discovery of such skyrmions in thin magnetic films and multilayers, already used in today’s technology, and the possibility to move these skyrmions at very low electrical current densities, has opened the perspective to use them as bits in novel data storage devices.

Up to now individual magnetic whirls were detected either by electron microscopy or by the resistance change in a tunnel contact with a magnetic probe. Employing a scanning tunneling microscope researchers of the University of Hamburg were now able to demonstrate that the resistance changes also when a non-magnetic metal is used in such a measurement.

‘In our experiment we can move a metallic tip over a surface with atomic-scale precision, and in this way we can measure the resistance at different positions in a skyrmion’ says Christian Hanneken, a PhD student in the group of Prof. Roland Wiesendanger. This enables the proof for the locally varying resistance within the magnetic whirl. ‘We found a resistance change of up to 100%, allowing a simple detection scheme for skyrmions’, as Dr. Kirsten von Bergmann explains.

In collaboration with theoretical physicists from the University of Kiel the researchers were able to identify the origin of the resistance change in the magnetic whirl: it is due to the canting between the atomic magnets from one atom to the next (see figure). The larger the angle between the adjacent atomic magnets, the stronger is the change in electrical resistance.

‘Electrons have a spin, and thus they interact with magnetic structures’, says Prof. Stefan Heinze from the University of Kiel. When the electrons are travelling through a magnetic whirl, they feel the canting between the atomic magnets, leading to a local resistance change of the material. ‘We were able to understand this effect by performing extensive numerical computer simulations of the electronic properties and developed a simple model for this effect’, as the PhD student Fabian Otte explains.

In future applications this newly discovered effect could be exploited to read out skyrmionic bits in a simple fashion. The possibility to use arbitrary metallic electrodes significantly simplifies the fabrication and operation of such novel storage devices.


Original publication:
Electrical detection of magnetic skyrmions by tunnelling non-collinear magnetoresistance,
Christian Hanneken, Fabian Otte, André Kubetzka, Bertrand Dupé, Niklas Romming, Kirsten von Bergmann, Roland Wiesendanger and Stefan Heinze, Nature Nanotechnology, Online publication: 05.10.2015,
DOI: 10.1038/nnano.2015.218.

Additional information:
Dr. Kirsten von Bergmann
Universität Hamburg
Jungiusstr. 9A/11A
D-20355 Hamburg
Germany
e-mail: kbergman@physnet.uni-hamburg.de
Phone: +49- 40 - 4 28 38 - 62 95

Weitere Informationen:

http://www.nanoscience.de
http://www.sfb668.de

Heiko Fuchs | idw - Informationsdienst Wissenschaft

More articles from Information Technology:

nachricht New Foldable Drone Flies through Narrow Holes in Rescue Missions
12.12.2018 | Universität Zürich

nachricht NIST's antenna evaluation method could help boost 5G network capacity and cut costs
11.12.2018 | National Institute of Standards and Technology (NIST)

All articles from Information Technology >>>

The most recent press releases about innovation >>>

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

Im Focus: Data storage using individual molecules

Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.

Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...

Im Focus: Data use draining your battery? Tiny device to speed up memory while also saving power

The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.

Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Formed to Meet Customers’ Needs – New Laser Beams for Glass Processing

17.12.2018 | Physics and Astronomy

Preserving soil quality in the long term

17.12.2018 | Architecture and Construction

New RNA sequencing strategy provides insight into microbiomes

17.12.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>