TRANSPORT AND THERMODYNAMIC PROPERTIES OF CEAUAL3

We present measurements of the specific heat, the electrical resistivi ty, the Hall effect, and the magnetic susceptibility of CeAuAl3, a new heavy-electron compound that crystallizes in an ordered derivative of the tetragonal BaAl4-type structure. For comparison we have also done some of these measurements on the isostructural non-magnetic referenc e compound LaAuAl3, which appears to be a simple metal. Below T-N = 1. 32K, CeAuAl3 orders antiferromagnetically and below 1K, we encounter F ermi liquid behaviour with considerably enhanced effective masses, i.e ., a quadratic temperature dependence of the resistivity with a large prefactor and a sizable linear-in-T contribution to the specific heat. This linear-in-T contribution increases by more than a factor 50 from its value at T much greater than T-N to its value at T < T-N. Consequ ently CeAuAl3 develops a heavy-electron ground state, coexisting with antiferromagnetic order. The small energy scales involved in the probl em make CeAuAl3 a good candidate for tuning it, by varying external pa rameters, towards a quantum critical point. At high temperatures we ob serve local moment behaviour. From the temperature dependence of the m agnetic susceptibility and the specific heat we have derived the cryst alline-electric-field-split level scheme of the Ce3+ J = 5/2 multiplet . Distinct features in the electrical resistivity provide additional e vidence for this level splitting.