The team's findings point toward an oscillator that would harness the spin of electrons to generate microwaves—electromagnetic waves in the frequencies used by mobile devices. Electron spin is a fundamental property, in addition to basic electrical charge, that can be used in electronic circuits. The discovery adds another potential effect to the list of spin's capabilities.
The team's work—a novel variation on several types of previously proposed experimental oscillators—predicts that a special type of stationary wave called a "soliton" can be created in a layer of a multilayered magnetic sandwich. Solitons are shape-preserving waves that have been seen in a variety of media. (They first were observed in a boat canal in 1834 and now are used in optical fiber communications.) Creating the soliton requires that one of the sandwich layers be magnetized perpendicular to the plane of the sandwiched layers; then an electric current is forced through a small channel in the sandwich. Once the soliton is established, the magnetic orientation oscillates at more than a billion times a second.
"That's the frequency of microwaves," says NIST physicist Thomas Silva. "You might use this effect to create an oscillator in cell phones that would use less energy than those in use today. And the military could use them in secure communications as well. In theory, you could change the frequency of these devices quite rapidly, making the signals very hard for enemies to intercept or jam."
Silva adds that the oscillator is predicted to be very stable—its frequency remaining constant even with variations in current—a distinct practical advantage, as it would reduce unwanted noise in the system. It also appears to create an output signal that would be both steady and strong.
The team's prediction also has value for fundamental research.
"All we've done at this point is the mathematics, but the equations predict these effects will occur in devices that we think we can realize," Silva says, pointing out that the research was inspired by materials that already exist. "We'd like to start looking for experimental evidence that these localized excitations occur, not least because solitons in other materials are hard to generate. If they occur in these devices as our predictions indicate, we might have found a relatively easy way to explore their properties."
* M.A. Hoefer, T.J. Silva and M.W. Keller. Theory for a dissipative droplet soliton excited by a spin torque nanocontact. Physical Review B, 82, 054432 (2010), Aug. 30. 2010. DOI: 10.1103/PhysRevB.82.054432
Chad Boutin | EurekAlert!
Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst
Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy