Superconductivity mechanism

Physicists worked for many years to find a theory that explained superconductivity. To begin with, it looked as though the lattice played no part in the superconducting mechanism as X-ray studies demonstrated that there was no change in either the symmetry or the spacing of the lattice when superconductivity occurred. However, in 1950, an isotope effect was first observed for a particular metal, the critical temperature was found to depend on the isotopic mass, M, such that... 

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. 

Superconducting Mechanism Incoporating Covalon Conduction and free Electrons... 

With this physical picture, we can begin to analyze other attributes due to this type of superconductivity mechanism. Let us assign the quasi-lfee electron concentration as N(e) and we shall see how it affects the superconductivity. For this discussion, refer to Fig. 8- (b) where the plasmon wave intensity is plotted against N(e) in arbitrary units. 

Chemical Engineering Thermodynamics Cryogenics Heat Exchangers Metallurgy, Mechanical Superconductivity Mechanisms Vacuum... 

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. 

Solid C50 (buckminsterfullerene) can be intercalated by alkali metal atoms to form MxC6o compounds where x = 1 6. The discovery that M3C60 displays superconductivity, with transition temperatures as high as 33 K, has promoted considerable research interest, including a number of solid state NMR studies of both the structure and superconductivity mechanisms in these compounds. 

From the previous discussion of experimental evidence the superconducting mechanism via ferromagnetic fluctuations can be ruled out since the ferromagetic polarization at pm where Tc is largest is still 65% of the maximum value at ambient pressure (Pfleiderer and Huxley, 2002). Therefore models based on the FM quantum critical point scenario that follow the original work of Fay and Appel (1980) are not relevant for UGe2. On the other hand the phe-... 

In order to confirm the scenario of the superconducting mechanism described at the beginning of this section, density of states at the Fermi level and phonons are important parameters to be looked at and are studied using different methods. 

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