HIGH-PRESSURE TRANSPORT-PROPERTIES OF M2-XCEXCUO4-Y SINGLE-CRYSTALS

The transport properties of the electron-doped cuprates M2-xCexCuO4 (M = Pr, Nd, and Sm) single crystals are investigated under hydrostatic pressure up to 2 GPa. The effects of pressure on both the c-axis (rho(c)) and the in-plane (rho(ab)) resistivity are measured from room temperature down to the superconducting state. It is found that at 300 K, d lnrho(ab)/dp almost-equal-to d lnrho(c)/dP almost-equal-to -3% GPa-1. The pressure does not change the temperature dependence of the normal-state resistivity, which at high temperature in both directions follows a rho approximately A(P)T2 law, but the coefficient A(P) lowers as pressure is increased. Moreover, we have found that for any lanthanide host (Pr, Sm, and Nd), the onset of superconductivity does not change with pressure (P < 2 GPa). These experimental results raise questions on the significance of the already proposed general behavior of d In T(c)/dP on T(c) and on the claimed ''antisymmetry'' of the pressure dependence of T(c) in electron-doped and hole-doped high-temperature superconductors.