Pressure-dependent resistivity studies and the origin of non-Fermi-liquid behaviour in UxY1-xPd3

We have studied the pressure and magnetic field dependence of the antiferromagnetic transition of U0.45Y0.55Pd3. TN increases with pressure whereas there is very little magnetic field dependence up to 7 T. These results indicate that (U, Y)Pd3 is located in the weak-coupling regime of the Doniach phase diagram, contradicting some previous suggestions. From a comparative study of the resistivity of U0.2Y0.8Pd3 under pressure and magnetic field, we have shown that the non-Fermi-liquid behaviour seen in this composition is very robust against pressure and field. By considering the metallurgical aspect of these two samples, we propose that disorder in the U concentration is likely to be responsible for the decrease of TN with increasing Y concentration, and eventually the appearance of non-Fermi-liquid behaviour in U0.2Y0.8Pd3. (author)