Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Putting a spin on logic gates

11.04.2017

A research collaboration in Germany develops a prototype for a spin-wave majority logic gate that uses wave interference for information processing

Computer electronics are shrinking to small-enough sizes that the very electrical currents underlying their functions can no longer be used for logic computations in the ways of their larger-scale ancestors. A traditional semiconductor-based logic gate called a majority gate, for instance, outputs current to match either the "0" or "1" state that comprise at least two of its three input currents (or equivalently, three voltages). But how do you build a logic gate for devices too small for classical physics?


The brass block serves as an electric ground plate ensuring an efficient insertion of the RF currents to the antennae and, on the other hand, microwave connectors mounted to the block allow for the embedding of the device into our microwave setup.

Credit: Fischer/Kewenig/Meyer

One recent experimental demonstration, the results of which are published this week in Applied Physics Letters, from AIP Publishing, uses the interference of spin-waves -- synchronous waves of electron spin alignment observed in magnetic systems. The spin-wave majority gate prototype, made of Yttrium-Iron-Garnet, comes out of a new collaborative research center funded by the German Research Foundation, named Spin+X. The work has also been supported by the European Union within the project InSpin and has been conducted in collaboration with the Belgian nanotechnology research institute IMEC.

"The motto of the research center Spin+X is 'spin in its collective environment,' so it basically aims at investigating any type of interaction of spins -- with light and matter and electrons and so on," said Tobias Fischer, a doctoral student at the University of Kaiserslautern in Germany, and lead author of the paper. "More or less the main picture we are aiming at is to employ spin-waves in information processing. Spin waves are the fundamental excitations of magnetic materials."

So instead of using classical electric currents or voltages to send input information to a logic gate, the Kaiserslautern-based international team uses vibrations in a magnetic material's collective spin -- essentially creating nanoscale waves of magnetization that can then interfere to produce Boolean calculations.

"You have atomic magnetic moments in your magnetic material which interact with each other and due to this interaction, there are wave-like excitations that can propagate in magnetic materials," Fischer said. "The particular device we were investigating is based on the interference of these waves. If you use wave excitations instead of currents [...] then you can make use of wave interference, and that comes with certain advantages."

Using wave interference to produce the majority gate's output provides two parameters to use in controlling information: the wave's amplitude, and phase. In principle, that makes this concept more efficient also since a majority gate can substitute up to 10 transistors in modern electronic devices.

"The device we were investigating consists of three inputs where we excite waves and they combine," Fischer said. "Depending on the input phases where you encode the information, that determines the phase of the output signal, hence, defining the logic output state '0' or '1'. That is actually information processing and that's what we want."

This first device prototype, though physically larger than what Fischer and his colleagues see for eventual large-scale use, clearly demonstrates the applicability of spin-wave phenomena for reliable information processing at GHz frequencies.

Because the wavelengths of these spin waves are easily reduced to the nanoscale, so too (though perhaps not quite as easily) can be the gate device itself. Doing so may actually improve the functionality, reducing its sensitivity to unwanted field fluctuations. Besides, nano-scaling will increase spin-wave velocities that will allow for an increase in computing speed.

"What we aim for is the miniaturization of the device, and the smaller you make the device, the less sensitive it becomes to these influences," Fischer said. "If you look at how many wavelengths fit into this propagation length, the fewer there are, the less influence a change of the wavelength has on the output. So basically downscaling the device would also come with more benefits."

Furthermore, much like antennae, a single device can be operated at multiple frequencies simultaneously. This will allow for parallel computing using the same "core" of a future spin-wave processor.

"One of my colleagues in Kaiserslautern is into spin-wave multiplexing and de-multiplexing," Fischer said. "We are also going in that direction, to use multiple frequencies and that would be a good compliment [...] to this majority gate."

###

The article, "Experimental prototype of a spin-wave majority gate," is authored by T. Fischer, M. Kewenig, D. A. Bozhko, A. A. Serga, I. I. Syvorotka, F. Ciubotaru, C. Adelmann, B. Hillebrands and A. V. Chumak. The article will appear in Applied Physics Letters on April 10, 2017 (DOI: 10.1063/1.4979840) and can be accessed at http://aip.scitation.org/doi/full/10.1063/1.4979840.

ABOUT THE JOURNAL

Applied Physics Letters features concise, rapid reports on significant new findings in applied physics. The journal covers new experimental and theoretical research on applications of physics phenomena related to all branches of science, engineering, and modern technology. See http://apl.aip.org.

Media Contact

Julia Majors
media@aip.org
301-209-3090

 @jasonbardi

http://www.aip.org 

Julia Majors | EurekAlert!

More articles from Physics and Astronomy:

nachricht Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences

nachricht Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication
16.07.2018 | Chinese Academy of Sciences Headquarters

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Subaru Telescope helps pinpoint origin of ultra-high energy neutrino

16.07.2018 | Physics and Astronomy

Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides

16.07.2018 | Life Sciences

New research calculates capacity of North American forests to sequester carbon

16.07.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>