High Temperature Superconductors

Superconductivity was discovered in 1908 by Kammerlingh Onnes but it was decades before it found any practical applications and seventy years before a satisfactory understanding of the fundamental physics of superconductivity was reached. That understanding (in terms of electron-phonon interactions) was then refined to the point that theorists could confidently predict in the early 1980's that the highest temperature possible for superconductivity to exist was in the neighbourhood of 30 K. Since materials with transition temperatures of nearly that had already been found, it was understood that superconducting technology would always involve the use of expensive refrigeration and cryogens like liquid helium - and would therefore remain inaccessible to "routine" applications.

Fortunately, Nature rarely pays much attention to theorists.

In 1986 and 1987, new breakthrough discoveries were made in materials made from copper oxides ("cuprates") and the highest critical temperatures (Tc) for superconductivity soared through the "liquid nitrogen barrier" of 77 K, liberating the imaginations of scientists as well as the media to envision a future rich with cheap practical applications of superconductivity.
History of the Transistor: Invention to Marketplace | History of the Transistor: Invention to Marketplace [cont'd] | Commercialization of High-Temperature Superconductors [1992]

Ten years later, the scientific community still does not understand how it is possible for superconductivity to be achieved at such high temperatures. (Of course, as usual, many individual scientists are confident that they have found the answer.)
Art Freeman vs. Phil Anderson [ca. 1989] | Resonating Valence Bonds [cartoon version] | Resonating Valence Bonds [alt. cartoon version] | Zhang's SO(5) Superspin theory of HTSC: AF Vortex Cores?

This page is still (obviously) under construction . . . .

Periodic Table showing Superconducting Elements and HTSC components | HTSC and Related Materials [ca. 1989] | Electron Microscope pictures of Cava's LSCO sample, Jan 87 | Properties of the 1-2-3 YBCO Material | YBCO 1-2-3 crystal: Unit Cell | BSCCO 2201 and 2212 crystals: Unit Cells | MTSC without Copper: the Barium Bismuthates | YBCO(x) AF/SC Phase Diagram (x,T) | Planes, Chains and Empties: LSCO vs. YBCO | Planes, Chains and Empties in YBCO | Cascading Questions about Magnetism and Superconductivity | Coexistence of Magnetism and HTSC: Two Key Questions | Effects of x Inhomogeneity in YBCOx? | Coexistence of Magnetism and Superconductivity: What is "Microscopic"?

Here's something to worry about: overpublication in the field of HTSC.

When you look at some seemingly unrelated developments and Nobel prizes it is clear that the fates of superconductivity and µSR are inextricably intertwined. . . .

Jess H. Brewer
Last modified: Thu Mar 12 13:46:29 EST 1998 ±