Featured Research

from universities, journals, and other organizations

Advancing the limits for ultrafast nano-devices

Date:
July 10, 2014
Source:
University of Illinois College of Engineering
Summary:
A recent study provides new insights on the physical mechanisms governing the interplay of spin and heat at the nanoscale, and addresses the fundamental limits of ultrafast spintronic devices for data storage and information processing.

Ultrafast laser light creates heat transport through the nonmagnetic/ferromagnetic/nonmagnetic tri-layer. The thermal excitation in the ferromagnetic layer produces spin current in the adjacent nonmagnetic layer in a picosecond timescale.
Credit: Gyung-Min Choi

A recent study by researchers at the University of Illinois at Urbana-Champaign provides new insights on the physical mechanisms governing the interplay of spin and heat at the nanoscale, and addresses the fundamental limits of ultrafast spintronic devices for data storage and information processing.

"Electrons carry a charge as well as spin-angular momentum. In a typical charge current, electrons' spin-angular-momentum is random so there is no spin current," explained David Cahill, a professor of materials science and engineering at Illinois. "However when electrons move with a partial alignment of spin-angular-momentum, we call it spin current which is the key element for nanoscale spintronic devices.

"It is understood that spin current can rotate magnetization. In other words, we can use spin current to select "0" or "1" state of magnetic memory devices. For ultrafast operation of such nano-devices, generation of spin current in picoseconds -- one trillionth of a second -- a time-scale that is difficult to achieve using electrical circuits, is highly desired," Cahill added.

"In a typical electrical circuit approach, spin current is driven by voltage difference across the structure. In this work, we utilized differences in temperature to generate spin currents," explained Gyung-Min Choi, lead author of the paper, "Spin current generated by thermally-driven ultrafast demagnetization," published in Nature Communications.

"A metallic ferromagnet has three energy reservoirs: electrons, magnons, and phonons," Choi stated. "Using ultra-short laser light, we created temperature differences between these reservoirs of thermal energy for a few picoseconds. The temperature difference between electron and magnon drives an exchange of spin-angular-momentum.

"Thus, we transport spin-angular-momentum from magnons to electrons, and this transport leads to ultrafast spin current," Choi added. "We refer to this spin current as thermally-driven and believe that our results extend the emerging discipline of spin caloritronics into the regime of picosecond time scales.

The benefits of thermal generation over electric generation are two-fold, according to Choi.

"Thermal spin generation has a potential for higher efficiency than spin generation by electrical currents. Our work shows that thermal spin current can be large enough to rotate magnetization. Although the amount of spin current is still smaller than what would be required for practical applications, we show the potential of thermal generation.

"The second advantage is the fast timescale. The time scale of spin currents generated by electrical currents is limited to a few nanoseconds. In this work, we are able to create spin current with timescale of a few picoseconds. Picosecond generation of spin current is desirable for fast operation of magnetic memory devices."


Story Source:

The above story is based on materials provided by University of Illinois College of Engineering. Note: Materials may be edited for content and length.


Journal Reference:

  1. Gyung-Min Choi, Byoung-Chul Min, Kyung-Jin Lee, David G. Cahill. Spin current generated by thermally driven ultrafast demagnetization. Nature Communications, 2014; 5 DOI: 10.1038/ncomms5334

Cite This Page:

University of Illinois College of Engineering. "Advancing the limits for ultrafast nano-devices." ScienceDaily. ScienceDaily, 10 July 2014. <www.sciencedaily.com/releases/2014/07/140710081438.htm>.
University of Illinois College of Engineering. (2014, July 10). Advancing the limits for ultrafast nano-devices. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2014/07/140710081438.htm
University of Illinois College of Engineering. "Advancing the limits for ultrafast nano-devices." ScienceDaily. www.sciencedaily.com/releases/2014/07/140710081438.htm (accessed September 20, 2014).

Share This



More Computers & Math News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How To Protect Your Data In The Still-Vulnerable iOS 8

How To Protect Your Data In The Still-Vulnerable iOS 8

Newsy (Sep. 20, 2014) One security researcher says despite Apple's efforts to increase security in iOS 8, it's still vulnerable to law enforcement data-transfer techniques. Video provided by Newsy
Powered by NewsLook.com
How Much Privacy Protection Will Google's Android L Provide?

How Much Privacy Protection Will Google's Android L Provide?

Newsy (Sep. 19, 2014) Google's local encryption will make it harder for law enforcement or malicious actors to access the contents of devices running Android L. Video provided by Newsy
Powered by NewsLook.com
Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
What HealthKit Bug Means For Your iOS Fitness Apps

What HealthKit Bug Means For Your iOS Fitness Apps

Newsy (Sep. 18, 2014) Apple has delayed the launch of the HealthKit app platform, citing a bug. Video provided by Newsy
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