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mojo0529
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I've search plenty of papers,but I still got no idea about this.Can anyone give me some clues?
Thanks in advance.
Thanks in advance.
Since 1930 years Kikoin-Kitaygorodski-Chapnick empirical rule is known:Superconductivity in amorphous and microcrystalline transition-metal alloys*
W. L. Johnson and S. J. Poon
In: Journal of Applied Physics. Vol. 46, No. 4. April 1975
W. M. Keck Laboratory of Engineering Materials. California Institute of Technology, Pasadena, California 91109 (Received 2 October 1974)
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... It is found that the transition temperature of an amorphous phase obtained by liquid quenching is always less than that of one of the related crystalline phases...
Impurities can disrupt the regular lattice structure of a superconductor, hindering the flow of electrons and reducing the material's ability to conduct electricity without resistance. This leads to a decrease in Tc, as the superconductivity is more easily disrupted by thermal energy.
In some cases, impurities can actually increase Tc in certain superconductors. This is because the impurities can interact with the electrons in the material, creating a new type of superconducting state with a higher Tc. However, this is not a universal effect and depends on the type of impurities and the specific material.
Generally, impurities with a larger atomic mass and a different electronic structure from the host material have a bigger impact on Tc. This is because these impurities can more significantly disrupt the electron flow and create more scattering sites, reducing Tc. Examples of such impurities include oxygen, carbon, and different types of metals.
Impurities can also decrease the critical current density in superconductors. This is because they create more defects and imperfections in the lattice structure, making it more difficult for the superconducting current to flow without resistance. In addition, impurities can also limit the coherence length, which affects the maximum current that can be carried by the material.
Yes, the amount of impurities in a superconductor can be controlled through various fabrication techniques, such as doping or annealing. This allows for the optimization of Tc in different materials, as well as the creation of new types of superconductors with unique properties. However, it is a delicate balance, as too many impurities can significantly decrease Tc, while too few may not have a noticeable effect.