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Two-bands effect on the superconducting fluctuating diamagnetism in MgB&#8322

L. Romano'·A. Lascialfari·A. Rigamonti·I. Zucca
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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 to 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.

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L. Romano', A. Lascialfari, A. Rigamonti, I. Zucca. 2005-01-11. Two-bands effect on the superconducting fluctuating diamagnetism in MgB&#8322. https://doi.org/10.1103/physrevlett.94.247001

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