FORCE FIELDS 13
pear in numerous science fiction novels (such as the Ringworld series
written by Larry Niven in 1970).
For decades physicists have searched for room-temperature superconductors without successs. It has been a tedious, hit-or-miss process, testing one material after another. But in 1986 a new class of
substances called "high-temperature superconductors" was found that
became superconductors at about 90 degrees above absolute zero, or
90 R, creating a sensation in the world of physics. The floodgates
seemed to open. Month after month, physicists raced one another to
break the next world's record for a superconductor. For a brief moment
it seemed as if the possibility of room-temperature superconductors
would leap off the pages of science fiction novels and into our living
rooms. But after a few years of moving at breakneck speed, research in
high-temperature superconductors began to slow down.
At present the world's record for a high-temperature superconductor is held by a substance called mercury thallium barium calcium
copper oxide, which becomes superconducting at 138 R (-135°C). This
relatively high temperature is still a long way from room temperature.
But this 138 R record is still important. Nitrogen liquefies at 77 R, and
liquid nitrogen costs about as much as ordinary milk. Hence ordinary
liquid nitrogen could be used to cool down these high-temperature superconductors rather cheaply. (Of course, room-temperature superconductors would need no cooling whatsoever.)
Embarrassingly enough, at present there is no theory explaining
the properties of these high-temperature superconductors. In fact, a
Nobel Prize is awaiting the enterprising physicist who can explain how
high-temperature superconductors work. (These high-temperature
superconductors are made of atoms arranged in distinctive layers.
Many physicists theorize that this layering of the ceramic material
makes it possible for electrons to flow freely within each layer, creating a superconductor. But precisely how this is done is still a mystery.)
Because of this lack of knowledge, physicists unfortunately resort
to a hit-or-miss procedure to search for new high-temperature superconductors. This means that the fabled room-temperature supercon-
pear in numerous science fiction novels (such as the Ringworld series
written by Larry Niven in 1970).
For decades physicists have searched for room-temperature superconductors without successs. It has been a tedious, hit-or-miss process, testing one material after another. But in 1986 a new class of
substances called "high-temperature superconductors" was found that
became superconductors at about 90 degrees above absolute zero, or
90 R, creating a sensation in the world of physics. The floodgates
seemed to open. Month after month, physicists raced one another to
break the next world's record for a superconductor. For a brief moment
it seemed as if the possibility of room-temperature superconductors
would leap off the pages of science fiction novels and into our living
rooms. But after a few years of moving at breakneck speed, research in
high-temperature superconductors began to slow down.
At present the world's record for a high-temperature superconductor is held by a substance called mercury thallium barium calcium
copper oxide, which becomes superconducting at 138 R (-135°C). This
relatively high temperature is still a long way from room temperature.
But this 138 R record is still important. Nitrogen liquefies at 77 R, and
liquid nitrogen costs about as much as ordinary milk. Hence ordinary
liquid nitrogen could be used to cool down these high-temperature superconductors rather cheaply. (Of course, room-temperature superconductors would need no cooling whatsoever.)
Embarrassingly enough, at present there is no theory explaining
the properties of these high-temperature superconductors. In fact, a
Nobel Prize is awaiting the enterprising physicist who can explain how
high-temperature superconductors work. (These high-temperature
superconductors are made of atoms arranged in distinctive layers.
Many physicists theorize that this layering of the ceramic material
makes it possible for electrons to flow freely within each layer, creating a superconductor. But precisely how this is done is still a mystery.)
Because of this lack of knowledge, physicists unfortunately resort
to a hit-or-miss procedure to search for new high-temperature superconductors. This means that the fabled room-temperature supercon-