Anisotropic superconducting properties of MgB2 single crystals probed by in-plane electrical transport measurements - art. no. 140501

摘要

We report on the study of the electronic anisotropy of the MgB2 superconductor using the in-plane resistivity measurements in the magnetic field applied perpendicular and parallel to Mg and B planes of MgB2 single crystals. The results show the temperature dependent anisotropy of the upper critical field with the anisotropy ratio gamma=H-c2parallel to/H-c2perpendicular to increasing from 2.2 close to T-c up to about 3 below 30 K. Our estimation of the in-plane and out-of-plane coherence length of about xi(ab)(0)=68 Angstrom and xi(c)(0)=23 Angstrom and the electronic mean-free path l(ab)=240 Angstrom and l(c)=60 Angstrom, respectively, indicates MgB2 single crystal approaches the clean limit type-II superconductor. [References: 27]