POINT-CONTACT SPECTROSCOPY OF THE HEAVY-FERMION ANTIFERROMAGNET CECU5AU

The current-voltage characteristics of CeCu5Au point contacts have bee n measured for temperatures T = 0.06-3K and in magnetic fields up to B = 10T. The differential resistance dV/dI shows a minimum at zero bias followed by a maximum which vanishes at T approximate to 2K correspon ding roughly to the Neel temperature T-N of the bulk. It is possible t o describe the point-contact spectra assuming the contact is in the th ermal limit with a temperature dependent Lorenz number. The width of t he zero-bias minimum is almost independent of the magnetic field with an increase at B approximate to 5T indicating the suppression of the a ntiferromagnetic state within the point-contact region.