R.H.T. Wilke

The different development of the anisotropic upper critical field in MgB

The temperature dependence of the upper critical field, Hc2, for both field directions in partially substituted polycrystalline MgB2 was determined. Whereas the suppression of Tc is similar for aluminum and carbon substituted samples, Hc2 is affected by the substitution in profoundly different ways. In the case of Al substitution changes can tentatively be described by intrinsic effects (shift of the Fermi level). In the C substituted samples, Hc2 is increased drastically, and extrinsic effects (disorder) have to play a major role. The strong contrast between the two substitutions is discussed, taking into account three relevant scattering rates.

_2

Point-contact measurements on the carbon-substituted

by aluminum and carbon doping

mathrm{Mg}{({mathrm{B}}_{1ensuremath{-}x}{mathrm{C}}_{x})}_{2}

Systematic study of the two band/two gap superconductivity in carbon-substituted MgB2 by point-contact spectroscopy

filament/powder samples directly reveal a retention of the two superconducting energy gaps in the whole doping range from

Systematic study of the superconducting and normal-state properties of neutron-irradiated MgB2

x=0

Superconductivity in MgB2 doped with Ti and C

to

Effect of pressure on the superconducting transition temperature of doped and neutron-damaged MgB2

xensuremath{approx}0.1

Tuning the superconducting properties of magnesium diboride

. The large gap on the

Plasma Synthesized Doped B Powders for MgB2 Superconductors

ensuremath{sigma}

Synthesis of Mg(B1−xCx)2 powders

-band is decreased in an essentially linear fashion with increasing the carbon concentrations. The changes in the small gap