cans, however, nor did it endear him to the press.
In 1991, Sununu was accused of misusing govern-
ment aircraft for personal use. The resulting scandal
ended with his resignation on December 3, 1991.
Further Reading
Burke, John P.The Institutional Presidency: Organizing
and Managing the White House from FDR to Clinton.
2d ed. Baltimore: Johns Hopkins University Press,
2000.
Kessel, John H.Presidents, the Presidency, and the Politi-
cal Environment. Washington, D.C.: Congressional
Quarterly, 2001.
O’Neil, John.The Paradox of Success. New York:
Tarcher, 1994.
Thomas L. Erskine
See also Abortion; Bush, George H. W.; Conserva-
tism in U.S. politics; Dukakis, Michael; Elections in
the United States, 1988; Environmental movement.
Superconductors
Definition Elements, alloys, and ceramic
compounds through which electric current
flows without resistance
The discover y of high-temperature superconductors in the
late 1980’s by European and American researchers was
quickly recognized as extremely important by both scientists
and journalists, who emphasized such potential applica-
tions as magnetically levitated trains.
The discovery and development of superconduc-
tors, as well as their theoretical explanation and
practical applications, were due to the collective ef-
forts of many Europeans and Americans throughout
the twentieth century. In 1911, the Dutch physicist
Heiki Kamerlingh Onnes made the surprising dis-
covery that mercury, when cooled in liquid helium
to near absolute zero (about 4 Kelvins), permitted
electricity to flow through it without resistance. A
few decades later, German researchers found that
superconductors repelled magnetic fields, a phe-
nomenon later called the Meissner effect, after one
of its discoverers. In the late 1950’s, three American
physicists, John Bardeen, Leon Cooper, and John
Schrieffer, explained superconductivity in a mathe-
matical theory based on the movement of electron
pairs. This theory became known as the BCS theory,
from the first letter of each physicist’s last name. Im-
pressive as these early developments were, the 1980’s
became a nonpareil period of momentous discover-
ies in superconductivity.High-Temperature Superconductivity Before the
1980’s, all superconductivity research took place at
temperatures close to absolute zero, but in 1986, the
Swiss physicist Karl Alexander Müller and his youn-
ger German colleague, Johannes Georg Bednorz,
working at the International Business Machines
(IBM) research laboratory in Switzerland, made a
ceramic compound composed of the elements lan-
thanum, barium, copper, and oxygen. To their sur-
prise, this compound superconducted at the high-
est temperature then known for any substance, 35
Kelvins. When the researchers published this dis-
covery, it stimulated the search for substances that
superconducted at even higher temperatures, and it
also led to their winning the 1987 Nobel Prize in
Physics.
Two researchers who built on the work of Bed-
norz and Müller were Maw-Kuen Wu at the Univer-
sity of Alabama in Huntsville and Paul (Ching-Wu)
Chu at the University of Houston. Early in 1987,
Wu and his students made a new ceramic material
composed of yttrium, barium, copper, and oxygen
(YBCO) that appeared to superconduct at a temper-
ature much higher than any previous material. Paul
Chu, Wu’s doctoral dissertation adviser, used his so-
phisticated equipment to observe a transition in the
magnetic susceptibility of the YBCO ceramic mate-
rial at the astonishing temperature of 92 Kelvins.
The relatively high temperature of YBCO and other
materials’ superconductivity made it possible to con-
duct research at temperatures above 77 Kelvins, us-
ing the safer and more economical liquid nitrogen
rather than liquid helium.
Many scientists called high-temperature super-
conductors the “discovery of the decade,” and re-
search in the field exploded throughout the rest of
the 1980’s. Within six months of the initial discover-
ies, more than eight hundred papers were pub-
lished. These papers reported on the physical and
chemical properties of the new materials, as well as
on their detailed atomic arrangements. A variety of
new ceramic superconductors were made that chal-
lenged the tenets of the BCS theory. This theory
had successfully explained superconductivity in the
range of 4 to 40 Kelvins, but it had predicted a limitThe Eighties in America Superconductors 927