EFFECT OF PRESSURE ON THE MAGNETIC SUPERZONE GAP IN ANTIFERROMAGNETIC URANIUM-COMPOUNDS UCU2SN AND UCU3GA2

The effect of hydrostatic pressure on both the energy gap produced by magnetic superzone effects and the Neel temperature T(N) of UCu2Sn and UCu3Ga2 has been investigated by means of resistivity measurements. Under various pressures, the shape of the resistive transition below T(N) in both compounds remains unchanged, suggesting that the energy gaps are pressure-insensitive, whereas the transition merely moves to lower temperatures at a rate of approximately -0.1 K/kbar, indicating a negative pressure dependence of T(N) which is opposite to that of the usual binary and ternary uranium antiferromagnets.