Pressure dependence of<i>T</i>_cin the MgB₂super- conductor as probed by resistivity measurements

Abstract

High-pressure resistivity experiments were performed on the recently discovered superconductor, MgB2. Tc decreases quasi-linearly with applied pressure to 1.4 GPa at a rate of -2.0(1) K/GPa, which is somewhat larger than that derived from recently-reported ac susceptibility measurements. The reduction of Tc is 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(lnTc)/dV is significantly large.