Reversible magnetization of MgB2 single crystals with a two-gap nature

TL;DR

This study measures the reversible magnetization of MgB2 single crystals and demonstrates that their magnetic behavior is best explained by a two-gap superconductivity model, revealing detailed superconducting parameters.

Contribution

It provides the first detailed magnetization analysis of MgB2 single crystals using the Hao-Clem model, confirming the two-gap nature of superconductivity in MgB2.

Findings

Magnetization data fit a two-gap model better than single-gap theories.

Derived superconducting parameters such as Hc(0), Hc2(0), xi(0), lambda(0), and kappa.

Temperature dependence of lambda(T) supports two-gap superconductivity.

Abstract

We present reversible magnetization measurements on MgB2 single crystals in magnetic fields up to 2.5 T applied parallel to the crystal's c-axis. This magnetization is analyzed in terms of the Hao-Clem model, and various superconducting parameters, such as the critical fields [Hc(0) and Hc2(0)], the characteristic lengths [xi(0) and lambda(0)], and the Ginzburg-Landau parameter, kappa, are derived. The temperature dependence of the magnetic penetration depth, lambda(T), obtained from the Hao-Clem analysis could not be explained by theories assuming a single gap. Our data are well described by using a two-gap model.