Organic superconductors superconducting oxides

The coherence length in the organic superconductors is of the order of a lattice constant (as it is for the ceramic oxide superconductors). The organic superconductors are of type II (they have two critical fields). The dimensionality is between 1 and 2 (it is 3-D for the fullerides). For organic superconductors, the isotope effect results are unclear it is not certain which phonon modes are important for the superconductivity. 

For the ceramic oxide superconductors the mechanism of superconductivity is difficult to explain by standard BCS theory. For the organic superconductors, the superconductivity mechanism is probably of the BCS type. 

It is clear that no organic compound with a polymer chain of conjugation has been found to be superconducting. It is equally clear that all known superconductors are metal, compound alloy, or metal-oxide of some kind (including ceramics ). This fact suggests that the quasi-free electrons do play an important role in superconductivity. Thus, the key to the superconductivity mechanism should lie in a combination of Covalon-conduction and quasi-free electrons. 

First, practically nothing is said of the tremendous development in the so called HTCS, the new oxide superconductors. It could be argued that their metallic conductivity has been known much earlier than that of organic compounds. It is indeed a field by itself, which cannot possibly be dealt with here. It is, in a way, a great pity, as many similarities are observed, for instance between the oxide compounds and the organic charge transfer compounds, as stresses above normal , superconductive or antiferromagnetic properties, quasi low dimensionality, with exacerbated electron-electron interactions when localisation into Id is approached. .. 

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