High-pressure resistivity experiments were performed. It was found that TC decreased quasi-linearly with applied pressure to 1.4GPa at a rate of -2.0K/GPa, which was somewhat larger than that derived from alternating-current susceptibility measurements. The reduction of TC was consistent with the BCS picture, in a similar way to the C60-based superconductors. Taking into account the pressure dependence of the unit cell volume, V, the volume coefficient of TC, d(ln[TC])/dV was significantly large.

Pressure Dependence of TC in the MgB2 Superconductor as Probed by Resistivity Measurements. E.Saito, T.Taknenobu, T.Ito, Y.Iwasa, K.Prassides, T.Arima: Journal of Physics - Condensed Matter, 2001, 13, L267-70