Superconductivity is key to conserving energy; high magnetic field records
Date: Thursday, August 31, 2006 @ 21:40:43 GMT
Topic: Science


Dr. Fatih Dogan, a professor of materials science and engineering at the University of Missouri-Rolla, is working with superconducting materials that might eventually revolutionize the way energy is conserved.

Dogan is an author of a new article about the possible mechanisms of superconductivity at high temperatures. The paper was published this week by Nature Physics.


Superconductivity is a phenomenon that occurs in some materials at temperatures hundreds of degrees below zero. The phenomenon is characterized by exactly zero electrical resistance. In ordinary conductors the amount of resistance never reaches zero.

Normal conductors like copper generate heat, causing a certain amount of the energy transported through copper wires to be lost. For the same reason, a lot of energy is wasted in the processes of burning coal and oil. Superconducting materials don’t produce heat and are therefore much more energy efficient.

Fifty years ago, Nobel Prize-winning scientists explained the superconductivity of materials at low temperatures. But for the materials to be useful in the transportation of electricity, for example, they would have to be superconductive at much higher temperatures.

“Ideally, we’re talking room temperatures or higher,” Dogan says. “If we understand the mechanisms of high-temperature superconductivity, we could discover new materials that could be superconducting. Computers would work extremely fast without heating up and power lines could transport electricity on thin lines without losing energy.”

Dogan is working with a mixture containing versions of four elements: yttrium, barium, copper and oxygen. In a UMR lab, high-quality crystals of the mixture are grown. The crystals are used by physicists around the world for neutron scattering measurements.

“The periodic table has billions of possibilities,” Dogan says. “You have to have a good idea about what might work before you start.”

Dogan says physicists and other scientists around the world have been working on the superconductivity problem for a long time. Some of them have turned to Dogan, because he has developed a reputation for being able to grow large crystals of the complex elemental mixture that is believed to have unique qualities conducive to superconductivity at high temperatures.

Powder from the four elements is heated, melted, and then allowed to cool in a disc shape about the size of a silver dollar. The trick to getting the material in the disc to form as a single high-quality crystal, according to Dogan, is to place a seed crystal that melts at higher temperatures in the center of the mixture. Under precisely controlled conditions during the cooling process, the seed crystal colonizes the surrounding material.

Dogan’s crystals help physicists understand the mechanisms of high-temperature superconductivity. If more can be learned, new materials might one day be engineered to solve a lot of the world’s energy problems.

The latest Nature Physics paper is the sixth Nature publication on superconductivity materials that Dogan has co-authored.

Source: University of Missouri-Rolla
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Laboratory sets high magnetic field records

Scientists at the National High Magnetic Field Laboratory's Pulsed Field Facility at Los Alamos National Laboratory have set a pair of world records for nondestructive pulsed-magnet performance that puts them in position to deliver a magnet capable of achieving 100 tesla, the longstanding goal of magnet designers and researchers around the globe.

A 100-tesla magnet could have a profound impact on a wide range of scientific investigations, from studies of how materials behave under the influence of very high magnetic fields to research into the microscopic behavior of phase transitions.

Earlier this month, Pulsed Field Facility staff completed commissioning of an outer set of coils for a massive magnet being designed and assembled at Los Alamos. During the commissioning, the coil produced a peak magnetic field intensity of 35 tesla within the coil's 225 millimeter-diameter bore. This achievement is significant because of the record large volume in which the 35-tesla field was produced, and because man-made fields of this strength have never before been produced without the use of highly destructive, explosives-driven, field-generating technologies.

This latest achievement comes on the heels of another record set earlier this summer in which the newly developed pulsed-magnet prototype, in evaluation at the Pulsed Field Facility, was put through a series of tests intended to establish the operational limits of the current generation of pulsed- magnet technology. That magnet reached 80 tesla 10 times before experiencing a fault.

"The ability to produce a record high field in such a large volume is an important milestone in delivering a magnet capable of 100 tesla," said Alex Lacerda, head of the Pulsed Field Facility. "Several other laboratories around the world have attempted to deliver similar magnet systems without success, so the achievement is further evidence of how engineers, scientists, and technicians at the National High Magnetic Field Laboratory continue to set the world standard for magnet technology. We look forward to giving our users routine access to pulsed fields that in the past could only be imagined."

Once completed, the entire magnet will be a combination of seven coil sets weighing nearly 18,000 pounds and powered by jolts from a massive 1,200 megajoules motor generator. When fully commissioned, the magnet will be able to provide hundreds of milliseconds levels of magnetic field intensity never before achieved.

The study of materials behavior at the extreme conditions of temperature, pressure, and magnetic fields is a vital component of Los Alamos research aimed at understanding of the physics of structurally complex systems at a quantum level. These recent successes were enabled by long-term support from the U.S. Department of Energy's Office of Basic Energy Sciences and the National Science Foundation's 100 Tesla Multi-Shot magnet program.

Source: Los Alamos National Laboratory

(articles from: http://www.physorg.com)






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