Featured Research

from universities, journals, and other organizations

Brown-Led Team Observes Melting In A Superconductor

Date:
January 24, 2001
Source:
Brown University
Summary:
Researchers from Brown University and the National Institute of Standards and Technology are the first to directly observe the melting of a vortex lattice in a superconductor. Their discovery provides a model for the study of melting, a physical phenomenon that has eluded generations of physicists.

PROVIDENCE, R.I. — How do solids melt? Scientists have been trying to answer this deceivingly simple question for years. Now a team of researchers led by Brown University physicist Sean Ling has made a breakthrough discovery in a superconductor that will lead physicists closer to answering that question.

The team of Brown researchers, with colleagues from the National Institute of Standards and Technology in Gaithersburg, Md., are the first to show that swirling electrons, tightly packed in so-called quantized vortices, can literally melt or freeze just like ice or water. The results were published in Physical Review Letters on Jan. 22.

Ling and colleagues worked with a single crystal of the metal niobium, commonly used in magnets for MRI machines. The metal is a superconductor – it carries electric current without a loss of energy – at low temperatures.

The team took a cylinder of niobium 1 inch long by one-half inch in diameter and put it in a magnetic field, which causes the formation of vortices – swirling eddies of billions of Cooper pairs of electrons. Then, the metal was heated to see whether the vortex lattice would melt.

To create photographic evidence of melting, Ling’s team beamed billions of neutrons through the top of the cylinder. At the other end of the tunnel, the light formed spots when the vortices were solid (right), then a ring, which showed the scientists that the vortices had melted into a liquid (far right). The vortices were frozen solid at 4.1 degrees Kelvin and melted at 4.8 degrees Kelvin. (Photos of the melting are available at http://www.physics.brown.edu/users/faculty/xsling/ling_group/melt.jpg).

“This is of fundamental interest to physicists because it provides a playground for studying the phenomenon of melting,” Ling said. “It’s a common phenomenon, but understanding of this has evaded generations of physicists. Now we can actually use superconductors as a model system to study the mechanism of melting – it paves the way for future studies.”

The experiment also showed that the melting occurs at the same time as the superconductor’s well-known “peak effect,” a sudden increase of critical current followed by a sudden decrease. The higher current-carrying capability is thought to be caused by a softening of the vortex lattice into a Jell-O like consistency.

The research team includes graduate student Sang Ryul Park and undergraduate Bridget McClain of Brown University and Sungmin Choi, Daniel Dender and Jeffrey Lynn of the National Institute of Standards and Technology in Gaithersburg, where the neutron-producing nuclear reactor is maintained by the U.S. Department of Commerce.

The work was supported by grants from the National Science Foundation, the A.P. Sloan Foundation, and a Brown University Salomon Award.


Story Source:

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


Cite This Page:

Brown University. "Brown-Led Team Observes Melting In A Superconductor." ScienceDaily. ScienceDaily, 24 January 2001. <www.sciencedaily.com/releases/2001/01/010124075349.htm>.
Brown University. (2001, January 24). Brown-Led Team Observes Melting In A Superconductor. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2001/01/010124075349.htm
Brown University. "Brown-Led Team Observes Melting In A Superconductor." ScienceDaily. www.sciencedaily.com/releases/2001/01/010124075349.htm (accessed August 1, 2014).

Share This




More Matter & Energy News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
7 Ways to Use Toothpaste: Howdini Hacks

7 Ways to Use Toothpaste: Howdini Hacks

Howdini (July 30, 2014) Fresh breath and clean teeth are great, but have you ever thought, "my toothpaste could be doing more". Well, it can! Lots of things! Howdini has 7 new uses for this household staple. Video provided by Howdini
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
Smartphone Powered Paper Plane Debuts at Airshow

Smartphone Powered Paper Plane Debuts at Airshow

AP (July 30, 2014) Smartphone powered paper airplane that was popular on crowdfunding website KickStarter makes its debut at Wisconsin airshow (July 30) Video provided by AP
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