Electron diffusivities in MgB2 from point contact spectroscopy

Abstract

We demonstrate that the variation of the Andreev reflection with applied magnetic field provides a direct means of comparing the properties of MgB2 with the theory for a dirty two-band superconductor, and we find good agreement between the two. The ratio of electron diffusivities in the s and p bands can be inferred from this experiment. We find that the field dependence of the density of states at the Fermi level in the p band is independent of the field direction, and that the anisotropic upper critical field is determined by the anisotropic diffusivity in the s band.

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• Point-contact spectroscopy of Al- and C-doped MgB2. Superconducting energy gaps and scattering studies
• Investigation of Superconducting Gap Structure in TbFeAsO${}_{0.9}$F${}_{0.1}$ using Point Contact Andreev Reflection
• Point-contact spectroscopy in neutron-irradiated Mg^{11}B_2
• Enhanced superconductivity at the interface of W/Sr${}_2$RuO${}_4$ point contact
• Point-contact spectroscopy of the phononic mechanism of superconductivity in YB6
• Evidence for Nodal superconductivity in Sr${}_2$ScFePO${}_3$
• Microwave surface resistance of pristine and neutron-irradiated MgB2 samples in magnetic field
• Field-induced suppression of the pi-band superconductivity and magnetic hysteresis in the microwave surface resistance of MgB_2 at temperatures near T_c