Excess current in point contacts on two-band superconductor MgB$_2$ in magnetic field
arXiv:cond-mat/0403324 · doi:10.1016/j.ssc.2004.11.037
Abstract
Series of $I(V)$ characteristic and bias-dependent differential resistance $dV/dI(V)$ for point-contacts on the single crystals of two-band superconductor MgB$_2$ were measured in magnetic field up to 9 T. We have obtained magnetic field dependences of the excess current on the $I(V)$ curves and analyzed them using Koshelev and Golubov (Phys. Rev. Lett. {\bf 90}, 177002 (2003)) theoretical results for the mixed state of a dirty two-band superconductor. Introducing a simple model for the excess current in the point contact in the mixed state our data can be qualitatively described utilizing theoretical magnetic filed behavior of the $Ï$ and $Ï$-band superconducting order parameters and the corresponding averaged electronic density of states in MgB$_2$.
4 pages, 3 figs, RevTex4; V2: plain text improved, BTK fit is added to insets of Fig.3