Temperature dependence of H/sub c2/ and K$sub 1$ in strong coupling superconductors
According to the law of corresponding states, the properly scaled critical fields of a BCS superconductor are universal funetions of the reduced temperature T/T/sub c/. In realistic superconductors strong-coupling effects can cause deviations from this universal behavior. Numerical results are presented for the strong-coupling anomalies in the temperature dependence of the upper critical field H/sub c2/ and the Ginzburg-Landau parameter kappa /sub 1/. The calculations are based on the Eliashberg theory for strongcoupling superconductors and are performed for several realistic superconductors as well as for a series of model superconductors with increasing coupling strength. It is demonstrated that the magnitude of the deviations can be estimated from the magnitude of the ratio T/sub c/,/< omega >, where < omega > is an average phonon frequency. This rule does not apply to amorphous superconductors. The reason for this is shown to be due to the large weight of alpha /sup 2/F( omega ) at low frequencies which has been observed in these materials. (auth)
- Research Organization:
- Kernforschungsanlage, Juelich, Ger.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-29-028126
- OSTI ID:
- 4333432
- Journal Information:
- J. Low Temp. Phys., v. 14, no. 5/6, pp. 501-519, Journal Name: J. Low Temp. Phys., v. 14, no. 5/6, pp. 501-519; ISSN JLTPA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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