Mixed state properties of superconducting MgB2 single crystals

TL;DR

This study investigates the magnetic properties of MgB2 single crystals, revealing anisotropic superconducting parameters and confirming its status as a clean limit, intermediate coupling superconductor with notable anisotropy effects.

Contribution

It provides detailed measurements of critical fields and anisotropy, demonstrating the applicability of Ginzburg-Landau and London models to MgB2.

Findings

Critical fields: Hc2^c(0)=3.2 T, Hc2^{ab}(0)=14.5 T

Anisotropy ratio γ=4.6

Superconductor in clean limit with intermediate coupling

Abstract

We report on measurements of the magnetic moment in superconducting MgB2 single crystals. We find \mu_0H_{c2}^c(0) = 3.2 T, \mu_0H_{c2}^{ab}(0) = 14.5 T, \gamma = 4.6, \mu_0H_c(0) = 0.28 T, and \kappa(T_c) = 4.7. The standard Ginzburg-Landau and London model relations lead to a consistent data set and indicate that MgB2 is a clean limit superconductor of intermediate coupling strength with very pronounced anisotropy effects.