TEMPERATURE-DEPENDENCE OF THE ANTIFERROMAGNETIC STATE IN URU2SI2 BY POINT-CONTACT SPECTROSCOPY

Point-contact spectroscopy has been used to study the temperature evol ution of the spin-density-wave (SDW) behavior of a URu2Si2 single crys tal. In the c direction at a temperature of 19 K, we observe the onset of an asymmetric structure in the dV/dI versus V characteristic, and this has been correlated with the development of a SDW gap. We observe that the data follow a BCS behavior. In addition, we have performed t unneling experiments that indicate that only portions of the Fermi sur face are being gapped. From these data we have measured the energy gap , 2DELTA = 11.7 meV, and the ratio 2DELTA/K(B)T(N) which gives a value of the order of 7.2.