Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Electric field shakes a magnet in one trillionth of a sec. Novel method of spin control discovered

04.10.2016

An international team of scientists from Germany, the Netherlands and Russia has successfully demonstrated a novel, highly efficient and ultrafast magnetization control scheme by employing electromagnetic waves oscillating at terahertz frequencies. The new concept will be published in the upcoming issue of Nature Photonics.

Although magnetism has been known from ancient times, a fundamental understanding of the origin of this physical phenomenon has been achieved only in the last 100 years.


An intense THz pulse (red waveform) changes the electronic orbitals of a magnetic material leading to oscillation of spins (compass needles).

Dr. Rostislav Mikhaylovskiy – Only to be used in connection with coverage about this press release.

Today, the simplest model of a magnet is based on electrons orbiting the atomic nuclei as the planets revolve around the sun. Moreover, like the planets gyrate around their rotational axes, the electrons exhibit a similar spinning.

Due to this spinning motion, an electron behaves as an elementary magnet, where the “spin” can be imagined as the quantum part of a compass needle. In many materials, the spins point in certain directions determined by the quantum mechanical properties of the orbital motion of the electrons. This direction is called the magnetic anisotropy axis.

The synergy of very many “needles” in a magnet can form magnetically polarized states like those used to store information in common hard drives. Opposite polarities of the needles (comparable to “north” and “south” of a real compass) correspond to the “0” and “1” states of a bit of information. In state-of-the-art magnetic recording technology, these bits are altered between “0” and “1” with the help of an external magnetic field strong enough to overcome the magnetic anisotropy axis.

The switching mechanism employed is physically restricted to a certain speed, so such technology is quickly reaching its fundamental limits. However, the rapidly increasing amount of information being recorded and archived calls for ever-faster magnetic recording. To meet this challenge, an international team of scientists from Regensburg, Nijmegen, Moscow, and Berlin has investigated a conceptually new way to control magnetism in an extremely rapid fashion by way of oscillating electric fields.

The researchers used the Regensburg high-field terahertz radiation source to generate strong pulses of electromagnetic radiation with duration on the order of one picosecond (1 picosecond = 10-12 s, the trillionth of a second). The centre frequency of the electromagnetic wave pulses is one terahertz (1 THz = 1012 Hz), i.e. between microwaves and visible light.

The terahertz electric field is strong enough to induce a voltage of a million volts over a distance of one centimeter. It thereby perturbs the orbital motion of the electrons and deflects the direction of the magnetic anisotropy axis. The spins have to follow their new equilibrium axis and start to oscillate.

Previously, researchers successfully used pulses of visible light or THz magnetic fields to deflect spins, but the interactions they employed were comparably weak. In contrast, in the present experiment, the amplitude of the magnetization oscillations scales quadratically with the driving THz electric field. Due to this nonlinear scaling, comparably weak THz fields (likely about one tenth of the ones expected for existing methods) should be sufficient to induce such strong oscillations in the spins that they change their directions.

This process would correspond to writing a bit of information into a magnetic storage device. Therefore, this new finding addresses the long-term technological ambition of a direct, high-speed manipulation of magnetic data bits by an electric field pulse. Additionally, for the first time, a nonlinear interaction mechanism between spins and short THz pulses has been exploited, marking a milestone of photonics on its own. These findings are of great importance for the understanding of light-magnetism interactions on extremely short timescales and for information technology of the future.


Original publication:
S. Baierl, M. Hohenleutner, T. Kampfrath, A.K. Zvezdin, A.V. Kimel, R. Huber and R.V. Mikhaylovskiy,
Nonlinear spin control by terahertz-driven anisotropy fields, Nature Photonics 2016
Publication: DOI: 10.1038/NPHOTON.2016.181


Contact:
Prof. Dr. Rupert Huber
Universität Regensburg
Chair for experimental and applied physics
phone: ++49 941 943-2071
e-mail: rupert.huber@ur.de

Dr. Rostislav Mikhaylovskiy
Radboud University
Institute for Molecules and Materials
phone: ++31 24365 3094
e-mail: r.mikhaylovskiy@science.ru.nl

Petra Riedl | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-regensburg.de/

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 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...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

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

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

14.12.2018 | Power and Electrical Engineering

Tangled magnetic fields power cosmic particle accelerators

14.12.2018 | Physics and Astronomy

In search of missing worlds, Hubble finds a fast evaporating exoplanet

14.12.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>