Featured Research

from universities, journals, and other organizations

Spintronic technologies: Advanced light source provides new look at skyrmions

Date:
June 25, 2014
Source:
DOE/Lawrence Berkeley National Laboratory
Summary:
Researchers for the first time have used x-rays to observe and study skyrmions, subatomic quasiparticles that could play a key role in future spintronic technologies.

Advanced Light Source images of a Cu2SeO3 sample show five sets of dual-peak skyrmion structures, highlighted by the white ovals. The dual peaks represent the two skyrmion sub-lattices that rotate with respect to each other. All peaks fall on an arc (dotted line) representing the constant amplitude of the skyrmion wave vector.
Credit: Image courtesy of DOE/Lawrence Berkeley National Laboratory

Skyrmions, subatomic quasiparticles that could play a key role in future spintronic technologies, have been observed for the first time using x-rays. An international collaboration of researchers working at Berkeley Lab's Advanced Light Source (ALS) observed skyrmions in copper selenite (Cu2SeO3) an insulator with multiferroic properties. The results not only hold promise for ultracompact data storage and processing, but may also open up entire new areas of study in the emerging field of quantum topology.

"Using resonant x-ray scattering, we were able to gather unique element-specific, orbital-sensitive electronic and magnetic structural information not available by any other method," says Sujoy Roy, a physicist who oversees research at ALS Beamline 12.0.2 where the study was carried out, and the corresponding author of a paper describing this research in Physical Review Letters titled "Coupled Skyrmion Sublattices in Cu2OSeO3."

"We found the unexpected existence of two distinct skyrmion sub-lattices that rotate with respect to each other, creating a moiré-like pattern," Roy says. "Compared to materials with a simpler magnetic structure, the sub-lattices provide for an extra degree of freedom to minimize the free energy. This leads to magnetic excitations that can't exist in materials with a single magnetic lattice structure."

Although skyrmions act like baryons, they are actually magnetic vortices -- discrete swirls of magnetism -- formed from the spins of charged particles. Spin is a quantum property in which the charged particles act as if they were bar magnets rotating about an axis and pointing in either an "up" or "down" direction. The discovery of skyrmions -- named for Tony Skyrme, a British physicist who first theorized their existence -- in manganese silicide generated much excitement in the materials sciences world because their exotic hedgehog-like spin texture is topologically protected -- meaning it can't be perturbed. Add to this the discovery that skyrmions can be moved coherently over macroscopic distances with a tiny electrical current and you have a strong spintronic candidate.

"A major breakthrough came with the discovery of skyrmions in copper selenite because its magnetic properties can be controlled with an electric field," says Roy. "To achieve this control, however, we must understand how different electron orbitals stabilize the skyrmionic phase. Until our study, the copper selenite skyrmions had only been observed with neutron scattering and transmission electron microscopy, techniques that are insensitive to electron orbitals."

ALS Beamline 12.0.2 is an undulator beamline with experimental facilities optimized for coherent x-ray scattering studies of magnetic materials. The collaboration, which included researchers from Berkeley Lab's Materials Sciences Division and Japan's RIKEN institute, used these facilities to first identify the magnetic vortex. Then, at a certain applied electric field and temperature, they saw x-ray signals due to the formation of a skyrmion lattice.

"We were able to show that although the skyrmions act like magnetic particles, their origin in copper selenite is electronic," says Matthew Langner, lead author of the Physical Review Letters paper. "We also found that temperature can be used to move the skyrmions in copper selenite in either a clockwise or counter-clockwise direction."

Controlling the movement of skyrmions in a multiferroic compound suggests these magnetic vortices could be used to read and write data. Skyrmions are considered especially promising for the holographic information storage concept known as magnetic race-track memory.

"The skyrmion is topologically distinct from the other ground-state magnetic structures, meaning it can be moved around the sample without losing its shape," Langner says. "The combination of this stability and the low magnetic and electric fields required for manipulating the skyrmions is what makes them potentially useful for spintronic applications."

In addition to device applications, the collaboration's findings show that is now possible to use x-rays to study spectroscopic and electronic aspects of the skyrmion, and to study skyrmion dynamics on the time-scale of fundamental interactions.

Co-authors of the Physical Review Letters paper, in addition to Roy and Langner, are Shrawan Mishra, Jason Lee, Xiaowen Shi, Muhammad Hossain, Yi-De Chuang, Shinichiro Seki, Yoshinori Tokura, Stephen Kevan and Robert Schoenlein.

This research was supported by the U.S. Department of Energy's Office of Science.


Story Source:

The above story is based on materials provided by DOE/Lawrence Berkeley National Laboratory. Note: Materials may be edited for content and length.


Journal Reference:

  1. M. C. Langner, S. Roy, S. K. Mishra, J. C. T. Lee, X. W. Shi, M. A. Hossain, Y.-D. Chuang, S. Seki, Y. Tokura, S. D. Kevan, R. W. Schoenlein. Coupled Skyrmion Sublattices in Cu2OSeO3. Physical Review Letters, 2014; 112 (16) DOI: 10.1103/PhysRevLett.112.167202

Cite This Page:

DOE/Lawrence Berkeley National Laboratory. "Spintronic technologies: Advanced light source provides new look at skyrmions." ScienceDaily. ScienceDaily, 25 June 2014. <www.sciencedaily.com/releases/2014/06/140625132544.htm>.
DOE/Lawrence Berkeley National Laboratory. (2014, June 25). Spintronic technologies: Advanced light source provides new look at skyrmions. ScienceDaily. Retrieved July 26, 2014 from www.sciencedaily.com/releases/2014/06/140625132544.htm
DOE/Lawrence Berkeley National Laboratory. "Spintronic technologies: Advanced light source provides new look at skyrmions." ScienceDaily. www.sciencedaily.com/releases/2014/06/140625132544.htm (accessed July 26, 2014).

Share This




More Matter & Energy News

Saturday, July 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) — Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) — TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) — Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) — When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins