A systematic study was made of the temperature-dependent resistivity and of Tc of a single crystal MgB2 sample as a function of point defect concentration. Linear but weak correlations were found between the decreasing superconducting critical temperature and the residual resistivity, with no variation in the slope of the ρ(T) curve at high temperature. These findings reinforced the existing picture of s-wave pairing for superconductivity. The inter-band scattering was low in spite of increasing disorder. Matthiessen’s rule was obeyed, even in this 2-band material.

Matthiessen's Rule in MgB2 - Resistivity and Tc as a Function of Point Defect Concentration. B.Sipos, N.Barisic, R.Gaal, L.Forró, J.Karpinski, F.Rullier-Albenque: Physical Review B, 2007, 76[13], 132504 (3pp)