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Upper limit of metastability of the vortex-free state of a two-dimensional superconductor in a nonuniform magnetic field

Thomas R. Lemberger, Adam Ahmed

DOI 10.1103/PhysRevB.87.214505 · Physical Review B

T1

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Abstract

We calculate the magnetic field above which vortices necessarily appear in a two-dimensional superconducting film in a nonuniform magnetic field applied near its center, as in two-coil measurements of superfluid density. Experiments suggest that free vortices appear when the Meissner screening current density is large enough that the free-energy barrier for separating tightly-bound vortex-antivortex (V-aV) pairs into free vortices is comparable to kBT, not at the much lower thermodynamic critical field. Specifically, we calculate the applied magnetic field above which there exists no metastable state without vortices. There is a simple analogy with the appearance of phase-slip centers in a one-dimensional superconducting wire.

Source-reported materials — not catalogue approval

FormulaReported Tc (K)Pressure (GPa)Type
Sn

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—Pressure not reportedunknown
In

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—Pressure not reportedunknown
Nb

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—Pressure not reportedunknown
MoGe

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—Pressure not reportedunknown

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