Featured Research

from universities, journals, and other organizations

Superconductivity switched on by magnetic field

Date:
December 22, 2013
Source:
Paul Scherrer Institut (PSI)
Summary:
Superconductivity and magnetic fields are normally seen as rivals – very strong magnetic fields normally destroy the superconducting state. Physicists have now demonstrated that a novel superconducting state is only created in the material CeCoIn5 when there are strong external magnetic fields. This state can then be manipulated by modifying the field direction. In strong fields, an additional second superconducting state is created which means that there are two different superconducting states at the same time in the same material. The new state is coupled with an anti-ferromagnetic order that appears simultaneously with the field.

Michel Kenzelmann adjusts the gas input into a high-field magnet used for the experiments on CeCoIn5 at the Spallation Neutron Source SINQ.
Credit: Paul Scherrer Institute/Markus Fischer

Superconductivity and magnetic fields are normally seen as rivals -- very strong magnetic fields normally destroy the superconducting state. Physicists at the Paul Scherrer Institute have now demonstrated that a novel superconducting state is only created in the material CeCoIn5 when there are strong external magnetic fields. This state can then be manipulated by modifying the field direction. The material is already superconducting in weaker fields, too. In strong fields, however, an additional second superconducting state is created which means that there are two different superconducting states at the same time in the same material. The new state is coupled with an anti-ferromagnetic order that appears simultaneously with the field. The anti-ferromagnetic order from whose properties the researchers have deduced the existence of the superconducting state was detected with neutrons at PSI and at the Institut Laue-Langevin in Grenoble.

These findings were published in the scientific journal Nature Physics.

The material CeCoIn5 is superconducting at very low temperatures. As expected, superconductivity is destroyed in the presence of very strong magnetic fields (in the case of this material above 12 Tesla). Researchers at the Paul Scherrer Institute have now demonstrated that before this happens, a new exotic state of the material is created in strong magnetic fields. In this state, an additional antiferromagnetic order is observed in addition to superconductivity, i.e. the magnetic moments (the "elementary magnets") in the material partly point in one direction and partly in the opposite direction in a regular manner. Symmetry arguments lead to the conclusion that a novel quantum state must be linked to this magnetic order.

Two types of superconductivity simultaneously

PSI researchers have examined the properties of this antiferromagnetic order and concluded that this novel quantum state corresponds to a second, independent superconducting state. Superconductivity occurs when electrons come together in a material in Cooper pairs that can move unimpeded through the material. From the Cooper pair perspective, there are different types of superconductivity which differ particularly in terms of the symmetry properties of the movement of the Cooper pairs. In the material examined here, there is a second superconducting state in addition to the already existing one. To use technical jargon, initially there is d-wave superconductivity which is joined in the exotic state by p-wave superconductivity.

Detected with neutrons

The antiferromagnetic order in the material was detected in neutron experiments at PSI's neutron source SINQ and at the Institut Laue-Langevin in Grenoble. In these experiments, a neutron beam passes through the material and then the investigators observe in which directions large numbers of neutrons are scattered. This permits conclusions about regular structures inside the material. In this case, an additional direction emerged in which many neutrons were diffracted at high magnetic fields. This corresponded to the antiferromagnetic order or, to be precise to a spin density wave. That means when you move in a certain direction through the material, the magnetic moments first point in one direction, become larger and then smaller and then point in the opposite direction, become bigger and then smaller again etc. If you draw the moments as arrows then their tips can be joined by a wave line.

In this material, the spin density waves can only run in two directions that are perpendicular to one another, i.e. they can appear in two different domains. The direction in which the spin density wave moves depends on the direction of the external magnetic field. When the direction of the magnetic field is altered, then for a specific direction the orientation of the spin density wave also changes abruptly. To prove this effect, the researchers built a special sample holder by means of which the sample could be tilted by very small degrees between the measurements.

Quantum state under control

"The observed behavior of the material was completely unexpected and is certainly not a purely magnetic effect," explains Michel Kenzelmann, head of the PSI research team. "This is a clear indication that in the material the new superconducting state occurs together with the spin density wave, as is also expected from symmetry arguments." The special feature of this state is that it is very closely linked to the magnetic order. This means that they both become stronger when the strength of the outer magnetic field is increased. Hence, by means of the external magnetic field, one can directly control the quantum state which is linked to superconductivity. The possibility of directly controlling quantum states may be important for possible future quantum computers. "Even if this particular material will probably not be used because of the low temperatures and strong magnetic domains required, our experiments show what this kind of control could, in principle, look like," adds Simon Gerber, first author of the publication.


Story Source:

The above story is based on materials provided by Paul Scherrer Institut (PSI). The original article was written by Paul Piwnicki. Note: Materials may be edited for content and length.


Journal Reference:

  1. Simon Gerber, Marek Bartkowiak, Jorge L. Gavilano, Eric Ressouche, Nikola Egetenmeyer, Christof Niedermayer, Andrea D. Bianchi, Roman Movshovich, Eric D. Bauer, Joe D. Thompson, Michel Kenzelmann. Switching of magnetic domains reveals spatially inhomogeneous superconductivity. Nature Physics, 2013; DOI: 10.1038/nphys2833

Cite This Page:

Paul Scherrer Institut (PSI). "Superconductivity switched on by magnetic field." ScienceDaily. ScienceDaily, 22 December 2013. <www.sciencedaily.com/releases/2013/12/131222160051.htm>.
Paul Scherrer Institut (PSI). (2013, December 22). Superconductivity switched on by magnetic field. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2013/12/131222160051.htm
Paul Scherrer Institut (PSI). "Superconductivity switched on by magnetic field." ScienceDaily. www.sciencedaily.com/releases/2013/12/131222160051.htm (accessed October 23, 2014).

Share This



More Matter & Energy News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) — Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) — Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) — As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com
What Is Magic Leap, And Why Is It Worth $500M?

What Is Magic Leap, And Why Is It Worth $500M?

Newsy (Oct. 22, 2014) — Magic Leap isn't publicizing much more than a description of its product, but it’s been enough for Google and others to invest more than $500M. 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:

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