Helping out a high-temperature superconductor

September 14, 2005

UPTON, NY -- Researchers at the U.S. Department of Energy's Brookhaven National Laboratory have discovered a way to significantly increase the amount of electric current carried by a high-temperature superconductor, a material that conducts electricity with no resistance. This is an important step in the drive to create superconductor-based electric and power-delivery devices, such as power transmission lines, motors, and generators. The results are explained in the September 12, 2005, online edition of Applied Physics Letters.

"In theory, superconducting materials can conduct an enormous amount of electric current. But when incorporated into actual devices, certain factors tend to limit the current," said Brookhaven materials scientist Qiang Li, a co-author on the paper. "We studied these factors and found that one, which we call 'substrate roughness,' can actually significantly increase the current-carrying capacity."

The superconducting material studied here consists of the elements yttrium, barium, copper, and oxygen. Dubbed YBCO, it is a member of a class of copper- and oxygen-containing superconductors called "cuprates." Cuprates are "high-temperature" superconductors because they superconduct at temperatures much "warmer" than conventional superconductors (although still very cold) -- for example, -300°F rather than -440°F. This difference, while not huge, is enough to make cuprates more viable for practical applications than materials that must be kept much colder.

In many of these applications, YBCO films are deposited onto a 'normal' metal surface (the "substrate"), forming components known as coated conductors. One of the factors widely thought to degrade the performance of coated conductors is the roughness of the metal surface.

To verify this, Li and his colleagues set out to study and measure how the roughness of the substrate affects the current-carrying capacity of YBCO.

The researchers deposited a YBCO layer onto a substrate prepared with two distinct areas: a rough, corrugated region with nanometer (billionth-of-a-meter) sized ridges and grooves, and a smooth region. This configuration allowed the group to directly compare the behavior of the YBCO film on both surface types. They were able to do this using electrical-transport measurement techniques, which track the amount of supercurrent passing through the material, and "magneto-optical" imaging, a technique used to study superconductors by following their magnetic behavior.

"What we found is remarkable and surprising," said lead author Zuxin Ye, a graduate student under Li's supervision. "Rather than limiting the current, the nanoscaled corrugated surface produces more than a 30 percent increase in the supercurrent carried by the YBCO films. This suggests that metal substrates with some degree of roughness at the nanoscale might help improve the performance of high-temperature superconductors."

The work is the result of a collaboration between scientists in Brookhaven Lab's Materials Science Department, the Condensed Matter Physics group within the Physics Department, and the Lab's Center for Functional Nanomaterials. It was supported by the Office of Basic Energy Sciences within the U.S. Department of Energy's Office of Science.
One of the ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE's Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization. Visit Brookhaven Lab's electronic newsroom for links, news archives, graphics, and more:

DOE/Brookhaven National Laboratory

Related Superconductors Articles from Brightsurf:

Progress in electronic structure and topology in nickelates superconductors
Recently, superconductivity was discovered in the hole-doped nickelates, wh ich provide us a new platform to study the mechanism of high-temperature superconductivity.

UCF researcher zeroes in on critical point for improving superconductors
Developing a practical ''room temperature'' superconductor is a feat science has yet to achieve.

Connecting two classes of unconventional superconductors
The understanding of unconventional superconductivity is one of the most challenging and fascinating tasks of solid-state physics.

Superconductors are super resilient to magnetic fields
A Professor at the University of Tsukuba provides a new theoretical mechanism that explains the ability of superconductive materials to bounce back from being exposed to a magnetic field.

New advance in superconductors with 'twist' in rhombohedral graphite
An international research team led by The University of Manchester has revealed a nanomaterial that mirrors the 'magic angle' effect originally found in a complex man-made structure known as twisted bilayer graphene -- a key area of study in physics in recent years.

A new way towards super-fast motion of vortices in superconductors discovered
An international team of scientists from Austria, Germany and Ukraine has found a new superconducting system in which magnetic flux quanta can move at velocities of 10-15 km/s.

Controlling superconductors with light
IBS scientists has reported a conceptually new method to study the properties of superconductors using optical tools.

Superconductors with 'zeitgeist' -- When materials differentiate between past and future
Physicists at TU Dresden have discovered spontaneous static magnetic fields with broken time-reversal symmetry in a class of iron-based superconductors.

Hydrogen blamed for interfering with nickelate superconductors synthesis
Prof. ZHONG Zhicheng's team at the Ningbo Institute of Materials Technology and Engineering has investigated the electronic structure of the recently discovered nickelate superconductors NdNiO2. They successfully explained the experimental difficulties in synthesizing superconducting nickelates, in cooperation with Prof.

A closer look at superconductors
From sustainable energy to quantum computers: high-temperature superconductors have the potential to revolutionize today's technologies.

Read More: Superconductors News and Superconductors Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to