Point-contact spectroscopy of the heavy-fermion antiferromagnet CeCu5Au

The current-voltage characteristics of CeCu5Au point contacts have been measured for temperatures T = 0.06-3 K and in magnetic fields up to B = 10 T. The differential resistance dV/dI shows a minimum at zero bias followed by a maximum which vanishes at T ∼ 2 K corresponding roughly to the Neel temperature TN of the bulk. It is possible to describe the point-contact spectra assuming the contact is in the thermal limit with a temperature dependent Lorenz number. The width of the zero-bias minimum is almost independent of the magnetic field with an increase at B ∼ 5 T indicating the suppression of the antiferromagnetic state within the point-contact region. (orig.)