Current-induced pair breaking in magnesium diboride

Pair-breaking critical current density of magnesium diboride

We report the investigation of the pair-breaking current density jd in magnesium diboride. At low current densities j, the transition temperature Tc shifts in the classic DTc( j)/Tc(0)}2@ j / jd(0)# 2/3 manner, with a projected jd(0)'2310 7 A/cm. Current-voltage curves at fixed temperatures yield a similar value for jd(0), with an overall jd(T) dependence consistent with Ginzburg-Landau theory....

Superconducting Properties of Graphene Doped Magnesium Diboride

Superconductivity of Magnesium Diboride: Theoretical Aspects

Anisotropy of the Sommerfeld coefficient in magnesium diboride single crystals.

The anisotropic field dependence of the Sommerfeld coefficient gamma has been measured down to B-->0 by combining specific heat and Hall probe magnetization measurements in MgB2 single crystals. We find that gamma(B,theta) is the sum of two contributions arising from the sigma and pi band, respectively. We show that gammasigma(B,theta)=B/Bc2(theta) where Bc2(theta)=Bc2ab/sqrt[sin2theta+Gamma2co...

Effects of carbon doping on superconductivity in magnesium diboride

We introduce carbon onto boron sites in MgB2 . The resulting changes in crystal lattice constants and superconducting transition temperature Tc are characterized by x-ray-diffraction, magnetic susceptibility, and electrical resistance measurements. The consequence of approximately 10% carbon doping of boron sites is a 1% contraction of the intraplane lattice dimension ~with no appreciable chang...