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

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.

References in corpus (4)

• Superconductivity of metallic boron in MgB_2
• Specific heat of MgB${}_2$ in a one- and a two-band model from first-principles calculations
• Effect of two gaps on the flux lattice internal field distribution: evidence of two length scales from muSR in Mg1-xAlxB2
• Superconducting Diamagnetic Fluctuations in MgB2

Cited by in corpus (4)

• Theory of fluctuations in a two-band superconductor
• Superconducting phase fluctuations in SmFeAsO${}_{0.8}$F${}_{0.2}$ from diamagnetism at low magnetic field above $T_c$
• Fluctuations in two-band superconductors in a strong magnetic field
• Non-conventional superconducting fluctuations in Ba(Fe1-xRhx)2As2 iron-based superconductors