Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Synchronized dynamic duos

29.08.2011
The ability to control how magnetic vortices gyrate together has potential application in magnetic devices

Crystals can guide and control light and electricity by creating spatially periodic energy barriers. An electron (or photon) can pass through these barriers only when it has a particular energy, allowing engineers to create switches and other electronic devices. Now, a team of researchers from Japan and India has taken a key step towards using crystals to control waves of magnetic orientation (magnons), with the potential to create magnetic analogues to electronic and optical devices, including memory devices and transistors.

Led by YoshiChika Otani at the RIKEN Advanced Science Institute, Wako, the researchers began by manufacturing tiny disks of ferromagnetic material. The magnetic domains of such disks arrange into vortices, which consist of in-plane circular patterns surrounding a core with out-of-plane magnetization. By applying an alternating current with a particular frequency to such disks, physicists can excite the vortices into a gyrating motion, which they can detect by measuring the voltage across a disk.

Otani and his colleagues found that a current oscillating at 352 megahertz could set the vortex of a single disk into motion. When they brought a second disk near the first one, however, this single resonant frequency split into two: one was lower than the original frequency, and the other was higher. This kind of resonance splitting is characteristic of any pair of interacting oscillators with similar energies, whether it be two molecules that are covalently bonded to each other, or two swinging pendula.

The frequency splitting observed in the researchers’ pair of disks indicated that the magnetic vortices in each were coupled together, even though the current was driving one disk only. The researchers showed through numerical simulation that the lower-frequency resonance corresponded to the two vortices rotating in phase with each other; the higher-frequency resonance corresponded to an out-of-phase rotation. Depending on whether the core polarizations of the two disks were pointing in the same or opposite directions, Otani and colleagues also observed different frequency pairs. This led to four distinct resonant frequencies in all.

The researchers could control the differences among the four resonant frequencies by changing the distance between disks, as well as the disk sizes. By demonstrating controllable pairing between adjacent magnetic vortices, the results point the way to more complex chains, lattices and crystals in which magnons can be finely controlled, says Otani. “Our next target is to engineer a structure in which macroscopic spin waves propagate only along particular crystallographic directions.”

The corresponding author for this highlight is based at the Quantum Nano-Scale Magnetics Team, RIKEN Advanced Science Institute

Reference:

Sugimoto, S., Fukuma, Y., Kasai, S., Kimura, T., Barman, A. & Otani, Y. Dynamics of coupled vortices in a pair of ferromagnetic disks. Physical Review Letters 106, 197203 (2011).

gro-pr | Research asia research news
Further information:
http://www.riken.jp
http://www.researchsea.com

More articles from Physics and Astronomy:

nachricht Researchers discover link between magnetic field strength and temperature
21.08.2018 | American Institute of Physics

nachricht Smallest transistor worldwide switches current with a single atom in solid electrolyte
17.08.2018 | Karlsruher Institut für Technologie (KIT)

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: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Biosensor allows real-time oxygen monitoring for 'organs-on-a-chip'

21.08.2018 | Medical Engineering

Researchers discover link between magnetic field strength and temperature

21.08.2018 | Physics and Astronomy

IHP technology ready for space flights

21.08.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>