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.

Two-bands effect on the superconducting fluctuating diamagnetism in MgB2 / L. Romanò, A. Lascialfari, A. Rigamonti, I. Zucca. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 94:24(2005), p. 247001.247001-1-4.

Two-bands effect on the superconducting fluctuating diamagnetism in MgB2

A. Lascialfari;
2005

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.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/8096
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