Pair breaking by magnetic impurities in ultrathin superconducting films: Tc degradation mechanisms in disordered superconductors

J. A. Chervenak; J. M. Valles, Jr.

doi:10.1103/PhysRevB.51.11977

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Pair breaking by magnetic impurities in ultrathin superconducting films: Tc degradation mechanisms in disordered superconductors

J. A. Chervenak, J. M. Valles, Jr.

DOI 10.1103/PhysRevB.51.11977 · Physical Review B

T1

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Abstract

The transition temperature, Tc, of ultrathin superconducting films depends strongly on their thickness. We doped quench condensed films of Pb0.9Bi0.1 on Ge with dilute concentrations of the magnetic impurity Gd to investigate how α’, the pair-breaking rate per magnetic impurity, varies with Tc. α’ varies by less than 15% and decreases with decreasing Tc for 4 K<Tc<6 K in agreement with a theory of perturbative disorder effects. For Tc<4 K, α’ increases slightly. Within a generalized Eliashberg theory, the data suggests that disorder reduces Tc in these films by enhancing repulsive Coulomb interactions in the Cooper channel.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Pb0.9Bi0.1 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	6.8	Pressure not reported	unknown
Pb0.9Bi0.1 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	6	Pressure not reported	midpoint
Pb0.9Bi0.1 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	2.35	Pressure not reported	midpoint