Superconductors, high temperature general properties

Superconductors, high temperature general properties, 12-73 to 74 phase diagram, 12-182 to 199 Supercooled water, 6-8... 

There are presently four famihes of high-temperature superconductors under investigation for practical magnet appheations. Table 11-25 shows that all HTS are copper oxide ceramics even though the oxygen content may vary. However, this variation generally has little effect on the phvsical properties of importance to superconductivity. 

The main lesson to be learned from the discovery of high temperature superconductors is that we are, in general, not yet clever enough to produce breakthrough compounds by design. Therefore, we must conduct exploratory synthesis of new compounds in order to discover their unexpected properties. ... 

The unusual features of the new high temperature superconductors have been outlined. It is suggested that further synthetic studies, using some general guidelines coupled with a few physical property measurements, of new oxides as well as nitrides, sulfides, hydrides, and perhaps even chlorides may well lead to more of these fascinating novel superconductors. 

Lattice mismatch. In semiconductor systems lattice mismatches of only a few percent, or less, are desired to reduce the number of dislocations in the film. In ceramic thin films larger mismatches (generally <15%) are tolerated because higher defect densities in the film are acceptable. In some situations a certain number of defects are actually beneficial to film properties (they can provide piiming sites in high-temperature superconductors that can trap magnetic flux lines). 

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