Field-induced quantum breakdown of superconductivity in magnesium diboride

Superconductivity of Magnesium Diboride: Theoretical Aspects

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...

Effects of two-band superconductivity on the flux-line lattice in magnesium diboride.

We present neutron scattering from the flux line lattice (FLL) in MgB2. Between 0.5 and 0.9 T the FLL undergoes a 30 degrees reorientation, and simultaneously the scattered intensity falls sharply consistent with the weaker superconducting pi band being suppressed with increasing field. We speculate that the pi and sigma bands favor different FLL orientations, and that the reorientation is driv...

Superconducting Properties of Graphene Doped Magnesium Diboride

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...