Measurements of the superconducting transition temperatures for Al-doped, C-doped and neutron-damaged–annealed MgB2 samples under pressure up to about 8kbar were presented. The dTC/dP values change systematically with the decrease of the ambient pressure TC in a regular fashion. The evolution of the pressure derivatives could be understood assuming that the change in phonon spectrum was a dominant contribution to dTC/dP.

Effect of Pressure on the Superconducting Transition Temperature of Doped and Neutron-Damaged MgB2. S.L.Budko, R.H.T.Wilke, M.Angst, P.C.Canfield: Physica C, 2005, 420[3-4], 83-7