Pressure effect on the magnetic penetration depth in MgB2 -: art. no. 094504

A study of the pressure effect on the magnetic penetration depth lambda in polycrystalline MgB2 was performed by measuring the temperature dependence of the magnetization under an applied pressure of 0.15 and 1.13 GPa. We found that lambda(-2) at low temperature is only slightly affected by pressure [Delta lambda(-2)/lambda(-2)=3.1(9)%], in contrast to cuprate superconductors, where, in the same range of pressure, a very large effect on lambda(-2) was found. Theoretical estimates indicate that most of the pressure effect on lambda(-2) in MgB2 arises from the electron-phonon interaction.