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