Question

a) The superconducting transition temperature of a simple metal is 8.0 K; (i) find the superconducting

energy gap of this superconductor in electron volt, (ii) sketch the behavior of electronic specific heat

of this superconductor in the temperature range of 12 K to 0 K, (iii) sketch the reflectivity of this

superconductor as a function of the frequency of electromagnetic radiation falling on it and find the

frequency at which reflectivity drops from 100%, (iv) a superconductor – insulator – superconductor

(S-I-S) junction is made from this superconductor. Sketch the current – voltage characteristics of this

S-I-S junction.

(b) Superconductor A is type – I and superconductor B is type – II. You are measuring the magnetization

(M) of these two superconductors as a function of magnetic field (H) at T << Tc. How do you think

the M vs H curve will look like for these two superconductors? (3)

(c) A cylindrical sample of a superconductor is place in a small but uniform magnetic field (H << Hc)

directed along the axis of the cylinder at T << Tc. Will the magnetic field penetrate the

superconductor? If yes, how deep from the surface? (the charge carrier density in the

superconductor is 5 x 1022/cm3. you may take free electron mass and electronic charge for your

calculation).

Answer 1