Two-Band Effect on the Superconducting Fluctuating Diamagnetism in MgB2

L. Romanò; A. Lascialfari; A. Rigamonti; I. Zucca

doi:10.1103/PhysRevLett.94.247001

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Two-Band Effect on the Superconducting Fluctuating Diamagnetism in MgB2

L. Romanò, A. Lascialfari, A. Rigamonti, I. Zucca

DOI 10.1103/PhysRevLett.94.247001 · Physical Review Letters

T1

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Abstract

The field dependence of the magnetization above the transition temperature Tc in MgB2 is shown to evidence a diamagnetic contribution consistent with superconducting fluctuations reflecting both the σ and π bands. In particular, the upturn field Hup in the magnetization curve, related to the incipient effect of the magnetic field in quenching the fluctuating pairs, displays a double structure, in correspondence with two correlation lengths. The experimental findings are satisfactorily described by the extension to the diamagnetism of a recent theory for paraconductivity, in the framework of a zero-dimensional model for the fluctuating superconducting droplets above Tc.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
MgB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	39.1	Pressure not reported	unknown