Los Alamos Scientists See New Mechanism for SuperconductivityNovember 24, 2008Laboratory researchers have posited an explanation for superconductivity that may open the door to the discovery of new, unconventional forms of superconductivity. In a November 20 Nature letter, research led by Tuson Park and Joe D. Thompson describes a new explanation for superconductivity in non-traditional materials-one that describes a potentially new state of matter in which the superconducting material behaves simultaneously as a nonmagnetic material and a magnetic material. Superconducting materials carry a current without resistance, usually when cooled to temperatures nearing the liquid point of helium (nearly 452 degrees below zero Fahrenheit). Superconductors are extremely important materials because they hold promise for carrying electricity from one place to another without current loss or providing indefinite electric storage capacity. However, the cost of cooling materials to such extremely low temperatures currently limits the practicality of superconductors. If superconductors could be designed to operate at temperatures closer to room temperature, the results would be revolutionary.
Traditional theories of superconductivity hold that electrons within certain nonmagnetic materials can pair up when jostled together by atomic vibrations known as phonons. In other words, phonons provide the "glue" that makes superconductivity possible. Park and his colleagues now describe a different type of "glue" giving rise to superconducting behavior. Park and his colleagues cooled a compound of Cerium, Rhodium and Indium to just above absolute zero, nearly minus 459 degrees Fahrenheit. At this temperature, the material exhibits superconducting behavior. However, they also subjected the crystal to pressure changes and a magnetic field to perturb the alignment of electrons within the material. "We introduced very high quantum fluctuations in the material," Park said. "In other words, we made the electrons like a traffic jam, where it would be very difficult for them to move." This electronic traffic jam would discourage electron pairing by phonons; nevertheless, the material continued to exhibit superconducting behavior. Based on the material's behavior under different pressures and temperatures, researchers believe that the material reaches a quantum critical point near absolute zero. At this quantum critical point, the material retained properties of a metal with highly ordered electrons and highly disordered ones-a previously undescribed state of matter. Park and his colleagues believe that this quantum critical point provides a mechanism to pair electrons into a quantum state that gives rise to superconducting behavior. In other words, the research helps explain a mechanism for superconductivity without phonons. "This quantum critical point could be analogous to a black hole," said Park. "We can see what is happening at or near the event horizon-superconductivity-but we cannot yet see inside to understand why." A new mechanism for the electron-pairing glue that gives rise to superconductivity could allow researchers to design new materials that exhibit superconducting materials at higher temperatures, perhaps even opening the door to the "Holy Grail" of superconducting materials-one that works at room temperature. Park's colleagues include: Vladimir Sidorov, Filip Ronning, Jian-Xin Zhu, Yoshifumi Tokiwa, Hanoh Lee, Eric Bauer, Roman Movshovich, John Sarrao and Joe D. Thompson. The research was supported by the U.S. Department of Energy's Office of Science and Office of Basic Energy Science and funded in part by Los Alamos National Laboratory. Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is operated by Los Alamos National Security, LLC, a team composed of Bechtel National, the University of California, The Babcock & Wilcox Company, and Washington Group International for the Department of Energy's National Nuclear Security Administration. Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health, and global security concerns. Los Alamos National Laboratory Science News and Science Current Events Tag Cloud This tag cloud is a visual representation of term frequencies of random science news topics with common terms grouped together and emphasized by their display size. Allergic Reaction Eating Disorder Enceladus Tuberculosis Milk Anxiety Nicotine Mitochondrial Planet Heart Transplant Discrimination Blood Vessel Broadband Endometriosis Hearing Muscular Dystrophy Brain function Fluorescence Enzymes Brain Cancer Nevirapine Restless Legs Syndrome Brain Imaging Viral Infection Aerosols
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Related Superconductivity Current Events and Superconductivity News Articles Argonne, UC scientists reach milestone in study of emergent magnetism Scientists at the U.S. Department of Energy's Argonne National Laboratory and the University of Chicago have reached a milestone in the study of emergent magnetism. Thinnest superconducting metal created A superconducting sheet of lead only two atoms thick, the thinnest superconducting metal layer ever created, has been developed by physicists at The University of Texas at Austin. Evidence of macroscopic quantum tunneling detected in nanowires A team of researchers at the University of Illinois has demonstrated that, counter to classical Newtonian mechanics, an entire collection of superconducting electrons in an ultrathin superconducting wire is able to "tunnel" as a pack from a state with a higher electrical current to one with a notably lower current, providing more evidence of the phenomenon of macroscopic quantum tunneling. Multiferroics -- making a switch the electric way Multiferroics are materials in which unique combinations of electric and magnetic properties can simultaneously coexist. New element found to be a superconductor Of the 92 naturally occurring elements, add another to the list of those that are superconductors. Iron-arsenic superconductors in class of their own Physicists at the U.S. Department of Energy's Ames Laboratory have experimentally demonstrated that the superconductivity mechanism in the recently-discovered iron-arsenide superconductors is unique compared to all other known classes of superconductors. Magnetism governs properties of iron-based superconductors Though a year has passed since the discovery of a new family of high-temperature superconductors, a viable explanation for the iron-based materials' unusual properties remains elusive. But a team of scientists working at the National Institute of Standards and Technology (NIST) may be close to the answer. Physicists offer new theory for iron compounds An international team of physicists from the United States and China this week offered a new theory to both explain and predict the complex quantum behavior of a new class of high-temperature superconductors. Secrets behind high temperature superconductors revealed Scientists from Queen Mary, University of London and the University of Fribourg (Switzerland) have found evidence that magnetism is involved in the mechanism behind high temperature superconductivity. Quantum dance: Discovery led by Princeton researchers could revolutionize computing An international team of scientists, led by a Princeton University group, has observed an exciting and strange behavior in electrons' spin within a new material that could be harnessed to transform computing and electronics. More Superconductivity Current Events and Superconductivity News Articles |
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