Featured Research

from universities, journals, and other organizations

Driving an electron spin vortex 'skyrmion' with a microcurrent

Date:
August 29, 2012
Source:
National Institute for Materials Science
Summary:
Scientists have succeeded in forming a skyrmion crystal, in which electron spin is aligned in a vortex shape, in a microdevice using the helimagnet FeGe, and driving the skyrmion crystal with an ultra-low current density less than 1/100,000 that of the current necessary to drive magnetic domain walls in ferromagnets.

Temperature (-23 Deg Celcius) Fig. :Magnetic structure observed by Lorentz transmission electron microscopy. (a) Helical stripe structure in the zero magnetic field. Dotted lines show the crystal grain boundary. (b) Skymrion crystal formed by applying a 150mT magnetic field perpendicular to the device. (c) Enlarged diagram of the skyrmion crystal. (d) Distribution of magnetization in a single skyrmion. Colors and arrows show the direction of electron spin in the skyrmion.
Credit: Image courtesy of National Institute for Materials Science

RIKEN, the University of Tokyo, and NIMS succeeded in forming a skyrmion crystal, in which electron spin is aligned in a vortex shape, in a microdevice using the helimagnet FeGe, and driving the skyrmion crystal with an ultra-low current density less than 1/100,000 that of the current necessary to drive magnetic domain walls in ferromagnets.

RIKEN (President: Ryoji Noyori), the University of Tokyo (President: Junichi Hamada), and the National Institute for Materials Science (NIMS; President: Sukekatsu Ushioda) succeeded in forming a skyrmion crystal, in which electron spin is aligned in a vortex shape, in a microdevice using the helimagnet FeGe, and driving the skyrmion crystal with a ultra-low current density less than 1/100,000 that of the current necessary to drive magnetic domain walls in ferromagnets. As a result of this research, it was possible to obtain guidelines for the realization of a technology for manipulating the states of magnetic information media with extremely low power consumption. This research result was achieved by a team headed by Dr. Xuizhen Yu, a Postdoctoral Researcher in the Strong-Correlation Physics Research Team of the Correlated Electron Research Group of the RIKEN Advanced Science Institute (ASI; Director: Kohei Tamao), Group Director Prof. Yoshinori Tokura of the University of Tokyo Graduate School of Engineering, and Dr. Koji Kimoto, Unit Director of the Surface Physics and Structure Unit, Advanced Key Technologies Division (Division Director: Daisuke Fujita) of NIMS.

Magnetic memory devices that use the direction of electron spin, which is the source of magnetism, as digital information have attracted attention as devices with the important features of high speed and non-volatility, etc. In recent years, numerous attempts have been made to manipulate that magnetic information electrically without utilizing a magnetic field. If a current is passed through a ferromagnet, it is possible to move the magnetic domain walls, which are the boundaries between domains where magnetization is upward-oriented and domains with downward orientation (at domain walls, the direction of magnetic spin gradually changes). Therefore, reversal of magnetization becomes possible and information can be written. However, in order to drive the domain walls in this manner, a large current density of at least approximately 105 A/cm2 was necessary. Because this causes large energy loss, in other words, large energy consumption, a method of manipulating magnetic information media with a smaller current density had been desired.

The research team investigated various functional magnetic materials, and in 2010, succeeded in forming and observing a skyrmion crystal by applying a weak magnetic field of less than 200 millitesla (mT) to a thin slice of the helimagnet FeGe at near room temperature. In the present research, the team fabricated microdevices with a length of 165μm, width of 100μm, and thicknesses of 100nm to 30μm using the same FeGe. When a magnetic field of approximately 150mT at temperatures from -23°C to near-room temperature (-3°C) was applied, skymrion crystals in which a stable skyrmion with a diameter of about 70nm was aligned in a triangular lattice shape were observed.

The team succeeded in driving the skymrion crystal with an ultra-low current density (the minimum density is approximately 5A/cm2), which is less than 1/100,000th that required to drive magnetic domain walls in conventional ferromagnets. The fact that the skymrion can be driven with this extremely low current density represents the first step toward the development of low power consumption magnetic memory devices using skymrions as an information medium. Various applications can also be expected in the field of spintronics, which is currently an area of active research as a next-generation electronic technology.

The main portion of the research result was achieved in the "Quantum Science on Strong Correlation" project (Core Researcher: Yoshinori Tokura) of the Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST) of the Japan Society for the Promotion of Science (JSPS), with system design by the Council for Science and Technology Policy, and was supported by the JSPS. Part of the research was also supported by the Strategic Basic Research Programs/ERATO (Exploratory Research for Advanced Technology) Type Research Projects of the Japan Science and Technology Agency (JST) and the Nanotechnology Network of Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT), and has been published in the online edition of the British science journal Nature Communications on August 7.


Story Source:

The above story is based on materials provided by National Institute for Materials Science. Note: Materials may be edited for content and length.


Cite This Page:

National Institute for Materials Science. "Driving an electron spin vortex 'skyrmion' with a microcurrent." ScienceDaily. ScienceDaily, 29 August 2012. <www.sciencedaily.com/releases/2012/08/120829112224.htm>.
National Institute for Materials Science. (2012, August 29). Driving an electron spin vortex 'skyrmion' with a microcurrent. ScienceDaily. Retrieved September 22, 2014 from www.sciencedaily.com/releases/2012/08/120829112224.htm
National Institute for Materials Science. "Driving an electron spin vortex 'skyrmion' with a microcurrent." ScienceDaily. www.sciencedaily.com/releases/2012/08/120829112224.htm (accessed September 22, 2014).

Share This



More Matter & Energy News

Monday, September 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Thousands March in NYC Over Climate Change

Thousands March in NYC Over Climate Change

AP (Sep. 21, 2014) — Accompanied by drumbeats, wearing costumes and carrying signs, thousands of demonstrators filled the streets of Manhattan and other cities around the world on Sunday to urge policy makers to take action on climate change. (Sept. 21) Video provided by AP
Powered by NewsLook.com
What This MIT Sensor Could Mean For The Future Of Robotics

What This MIT Sensor Could Mean For The Future Of Robotics

Newsy (Sep. 20, 2014) — MIT researchers developed a light-based sensor that gives robots 100 times the sensitivity of a human finger, allowing for "unprecedented dexterity." Video provided by Newsy
Powered by NewsLook.com
MIT BioSuit A New Take On Traditional Spacesuits

MIT BioSuit A New Take On Traditional Spacesuits

Newsy (Sep. 19, 2014) — The MIT BioSuit could be an alternative to big, bulky traditional spacesuits, but the concept needs some work. Video provided by Newsy
Powered by NewsLook.com
New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) — Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
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