The researchers can tailor the material, which seamlessly alternates between metal and oxide layers, to achieve extraordinary superconducting properties — in particular, the ability to transport much more electrical current than non-engineered materials.
The team includes experts from the University of Wisconsin-Madison, Florida State University and the University of Michigan. Led by Chang-Beom Eom, the Harvey D. Spangler Distinguished Professor of materials science and engineering and physics at UW-Madison, the group described its breakthrough March 3, 2013, in the advance online edition of the journal Nature Materials.
Superconductors, which presently operate only under extremely cold conditions, transport energy very efficiently. With the ability to transport large electrical currents and produce high magnetic fields, they power such existing technologies as magnetic resonance imaging and Maglev trains, among others. They hold great potential for emerging applications in electronic devices, transportation, and power transmission, generation and storage.
Carefully layered superconducting materials are increasingly important in highly sophisticated applications. For example, a superconducting quantum interference device, or SQUID, used to measure subtle magnetic fields in magnetoencephalography scans of the brain, is based on a three-layer material.
However, one challenge in the quest to understand and leverage superconductivity is developing materials that work at room temperature. Currently, even unconventional high-temperature superconductors operate below -369 degrees Fahrenheit.
An unconventional high-temperature superconductor, the researchers' iron-based "pnictide" material is promising in part because its effective operating temperature is higher than that of conventional superconducting materials such as niobium, lead or mercury.
The research team engineered and measured the properties of superlattices of pnictide superconductors. A superlattice is the complex, regularly repeating geometric arrangement of atoms — its crystal structure — in layers of two or more materials. Pnictide superconductors include compounds made from any of five elements in the nitrogen family of the periodic table.
The researchers' new material is composed of 24 layers that alternate between the pnictide superconductor and a layer of the oxide strontium titanate. Creating such systems is difficult, especially when the arrangement of atoms, and chemical compatibility, of each material is very different.
Yet, layer after layer, the researchers maintained an atomically sharp interface — the region where materials meet. Each atom in each layer is precisely placed, spaced and arranged in a regularly repeating crystal structure.
The new material also has improved current-carrying capabilities. As they grew the superlattice, the researchers also added a tiny bit of oxygen to intentionally insert defects every few nanometers in the material. These defects act as pinning centers to immobilize tiny magnetic vortices that, as they grow in strength in large magnetic fields, can limit current flow through the superconductor. "If the vortices move around freely, the energy dissipates, and the superconductor is no longer lossless," says Eom. "We have engineered both vertical and planar pinning centers, because vortices created by magnetic fields can be in many different orientations."
Eom sees possibilities for researchers to expand upon his team's success in engineering man-made superconducting structures. "There's a need to engineer superlattices for understanding fundamental superconductivity, for potential use in high-field and electronic devices, and to achieve extraordinary properties in the system," says Eom. "And, there is indication that interfaces can be a new area of discovery in high-temperature superconductors. This material offers those possibilities."
Funding from the U.S. Department of Energy Office of Basic Energy Sciences, National Science Foundation, and the Air Force Office of Scientific Research supported the researchers' work. Eom's collaborators include Eric Hellstrom's and David Larbalestier's group at Florida State University; and Xiaoqing Pan's group at the University of Michigan.
Renee Meiller, 608-262-2481, email@example.com
Chang-Beom Eom | EurekAlert!
New material for digital memories of the future
19.10.2017 | Linköping University
Electrode materials from the microwave oven
19.10.2017 | Technical University of Munich (TUM)
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
19.10.2017 | Materials Sciences
19.10.2017 | Materials Sciences
19.10.2017 | Physics and Astronomy