Writing in the July 6, 2006, issue of Nature, scientists working at the Commerce Department's National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR) in collaboration with physicists from the University of Tennessee (UT) and Oak Ridge National Laboratory (ORNL) report strong evidence that magnetic fluctuations are key to a universal mechanism for pairing electrons and enabling resistance-free passage of electric current in high-temperature superconductors.
An important missing piece in the puzzle of high-temperature superconductivity, the finding should boost efforts to develop a variety of useful technologies now considered impractical for conventional superconductors, which work at markedly lower temperatures. Examples include loss-free systems for storing and distributing electric energy, superconducting digital routers for high-speed communications, and more efficient generators and motors.
The team was led by Pengcheng Dai, a UT-ORNL joint professor.
"Our results unify understanding of the role of magnetism in high-temperature superconductivity and move the research community one step closer to understanding the underlying pairing mechanism itself," says NIST physicist Jeffrey Lynn, a member of the collaboration. Better understanding of the mechanism of high-temperature superconductivity may lead to the discovery of new materials in which electrical resistance vanishes at even warmer temperatures.
Objects of intense scientific and technological interest since their discovery in 1986, high-temperature superconductors work their magic in ways different than materials that become superconducting at significantly colder temperatures, as first observed in 1911. In these conventional superconductors, vibrations in the materials' atomic latticework mediate the pairing process that results in the unimpeded flow of electrons.
Scientists have ruled out vibrations, or phonons, as the likely electron matchmaker in high-temperature superconducting compounds. And while they have assembled important clues over the last two decades, researchers have yet to pin down the electron-pairing mechanism in the high-temperature superconductors.
"Various experiments and theories have suggested that this resonance--this sharp magnetic excitation--may be the glue needed to explain high-temperature superconductivity, but key pieces of evidence were missing," explains lead author Stephen Wilson, a UT graduate student.
Previous work by other researchers had determined that magnetism played a role in one of two major classes of high-temperature superconductors--those engineered with holes, or occasional vacancies where electrons normally would reside. But, until this work, carried out at NCNR and ORNL's High Flux Isotope Reactor, the underlying pairing mechanism in the other class--materials doped with an excess of electrons--eluded detection.
Using neutron probes, which are extremely sensitive to magnetism, the team was the first to observe a magnetic resonance in an electron-doped high-temperature superconductor, in a carefully engineered compound known as PLCCO. More importantly, the resonance energy was found to obey a well-established relationship universal to high-temperature superconductors, irrespective of type.
This demonstrated a fundamental link between magnetism and the superconducting phase, the researchers report. These observations and findings should open new avenues of research into the exotic properties of high-temperature superconductors, they write.
Mark Bello | EurekAlert!
'Super yeast' has the power to improve economics of biofuels
18.10.2016 | University of Wisconsin-Madison
Engineers reveal fabrication process for revolutionary transparent sensors
14.10.2016 | University of Wisconsin-Madison
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences