THE EFFECT OF PRESSURE ON THE ANTIFERROMAGNETIC AND SUPERCONDUCTING STATES OF HEAVY-FERMION UPD2AL3

The effect of a hydrostatic pressure (p less-than-or-equal-to 3.5 bar) on the antiferromagnetic (T(N) = 14.2 K) and superconducting transition (T(c) = 1.9 K) temperature of single-crystalline UPd2Al3 has been determined by means of resistivity measurements. The pressure effects are extremely small when compared to other heavy-fermion systems: dT(N)/dp = 0 +/- 3 mK kbar-1 and dT(c)/dp = -2.0 +/- 0.7 mK kbar-1. The effect of a hydrostatic pressure (p less-than-or-equal-to 5 kbar) on the antiferromagnetic phase boundary has been studied by means of high-field magnetization measurements (B less-than-or-equal-to 28 T). It is found that the antiferromagnetic phase boundary, which is located at B(c) = 18 T for a field in the hexagonal plane at T = 5 K, shifts to higher field values with pressure at a rate of 0.13 +/- 0.01 T kbar-1.