Featured Research

from universities, journals, and other organizations

Optical properties of a novel kind of magnetism probed

Date:
September 23, 2013
Source:
Massachusetts Institute of Technology
Summary:
Using low-frequency laser pulses, a team of researchers has carried out the first measurements that reveal the detailed characteristics of a unique kind of magnetism found in a mineral called herbertsmithite. In this material, the magnetic elements constantly fluctuate, leading to an exotic state of fluid magnetism called a "quantum spin liquid." This is in contrast to conventional magnetism, found in materials called ferromagnets -- where all of the magnetic forces align in the same direction, reinforcing each other -- or antiferromagnets, where adjacent magnetic elements align in opposite directions, leading to complete cancellation of the material's overall magnetic field.

Bar magnet with iron filings showing magnetic field pattern (stock image).
Credit: Awe Inspiring Images / Fotolia

Using low-frequency laser pulses, a team of researchers has carried out the first measurements that reveal the detailed characteristics of a unique kind of magnetism found in a mineral called herbertsmithite.

Related Articles


In this material, the magnetic elements constantly fluctuate, leading to an exotic state of fluid magnetism called a "quantum spin liquid." This is in contrast to conventional magnetism, found in materials called ferromagnets -- where all of the magnetic forces align in the same direction, reinforcing each other -- or antiferromagnets, where adjacent magnetic elements align in opposite directions, leading to complete cancellation of the material's overall magnetic field.

Although a spin-liquid state has previously been observed in herbertsmithite, there has never been a detailed analysis of how the material's electrons respond to light -- a key to determining which of several competing theories about the material is correct.

Now a team at MIT, Boston College and Harvard University has successfully carried out these measurements. The new analysis is reported in a paper in Physical Review Letters, co-authored by Nuh Gedik, the Biedenharn Career Development Associate Professor of Physics at MIT, graduate student Daniel Pilon, postdoc Chun Hung Lui and four others.

Their measurements, using laser pulses lasting just a trillionth of a second, reveal a signature in the optical conductivity of the spin-liquid state that reflects the influence of magnetism on the motion of electrons. This observation supports a set of theoretical predictions that have not previously been demonstrated experimentally. "We think this is good evidence," Gedik says, "and it can help to settle what has been a pretty big debate in spin-liquid research."

"Theorists have provided a number of theories on how a spin-liquid state could be formed in herbertsmithite," Pilon explains. "But to date there has been no experiment that directly distinguishes among them. We believe that our experiment has provided the first direct evidence for the realization of one of these theoretical models in herbertsmithite."

The concept of quantum spin liquids was first proposed in 1973, but the first direct evidence for such a material was only found within the last few years. The new measurements help to clarify the fundamental characteristics of this exotic system, which is thought to be closely related to the origins of high-temperature superconductivity.

Gedik says, "Although it is hard to predict any potential applications at this stage, basic research on this unusual phase of matter could help us to solve some very complicated problems in physics, particularly high-temperature superconductivity, which might eventually lead to important applications." In addition, Pilon says, "This work might also be useful for the development of quantum computing."

Leon Balents, a professor of physics at the University of California at Santa Barbara who was not involved in this work, says, "If the observed optical conductivity in these measurements is truly intrinsic, it is an important and exciting result, which will be very important in understanding the nature of the spin-liquid state."

Balents adds that further work is needed to confirm this result, but says "this is clearly an exciting and important measurement, which I hope will be pursued further by extending the frequency and magnetic field range in the future."

The work was supported by the U.S. Department of Energy, and also included Young Lee and Tian-Heng Han of MIT, David Shrekenhamer and Willie J. Padilla of Boston College, and graduate student Alex J. Frenzel of MIT and Harvard.


Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. The original article was written by David L. Chandler. Note: Materials may be edited for content and length.


Journal Reference:

  1. D. V. Pilon, C. H. Lui, T. -H. Han, D. Shrekenhamer, A. J. Frenzel, W. J. Padilla, Y. S. Lee, N. Gedik. Spin-Induced Optical Conductivity in the Spin-Liquid Candidate Herbertsmithite. Physical Review Letters, 2013; 111 (12) DOI: 10.1103/PhysRevLett.111.127401

Cite This Page:

Massachusetts Institute of Technology. "Optical properties of a novel kind of magnetism probed." ScienceDaily. ScienceDaily, 23 September 2013. <www.sciencedaily.com/releases/2013/09/130923114116.htm>.
Massachusetts Institute of Technology. (2013, September 23). Optical properties of a novel kind of magnetism probed. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2013/09/130923114116.htm
Massachusetts Institute of Technology. "Optical properties of a novel kind of magnetism probed." ScienceDaily. www.sciencedaily.com/releases/2013/09/130923114116.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Touch-Free Smart Phone Empowers Mobility-Impaired

Touch-Free Smart Phone Empowers Mobility-Impaired

Reuters - Innovations Video Online (Dec. 21, 2014) A touch-free phone developed in Israel enables the mobility-impaired to operate smart phones with just a movement of the head. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Building Google Into Cars

Building Google Into Cars

Reuters - Business Video Online (Dec. 19, 2014) Google's next Android version could become the standard that'll power your vehicle's entertainment and navigation features, Reuters has learned. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
AP Review: Nikon D750 and GoPro Hero 4

AP Review: Nikon D750 and GoPro Hero 4

AP (Dec. 19, 2014) What to buy an experienced photographer or video shooter? There is some strong gear on the market from Nikon and GoPro. The AP's Ron Harris takes a closer look. (Dec. 19) Video provided by AP
Powered by NewsLook.com
Obama: Better Ways to Create Jobs Than Keystone Pipeline

Obama: Better Ways to Create Jobs Than Keystone Pipeline

AFP (Dec. 19, 2014) US President Barack Obama says that construction of the Keystone pipeline would have 'very little impact' on US gas prices and believes there are 'more direct ways' to create construction jobs. Duration: 00:47 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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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