Field Dependence of the Specific Heat of Single-Crystalline ZrZn2

ĽA. Faißt1, C. Pfleiderer1, M. Uhlarz1, H. v. Löhneysen1,2, S. M. Hayden3 und G. G. Lonzarich4
1Physikalisches Institut, Universität Karlsruhe
2Forschungszentrum Karlsruhe, Institut für Festkörperphysik
3University of Bristol, Bristol BS8 1TL, UK
4University of Cambridge, Cambridge CB3 0HE, UK

We present measurements of the specific heat C of a single crystal of ZrZn2 in the range 2 K to 30 K, in an applied magnetic field B up to 14 T. For B = 0 and low temperature (T < 7K) the specific heat varies as C » gT+bT3 , where g » 45  mJ/mol K2 and b corresponds to a Debye temperature QD » 340 K in agreement with earlier work. Magnetic field reduces g by up to 30 % at 14 T. The variation of g with B is compared with predictions of a self-consistent model of the magnetic equation of state, where phenomenological parameters are taken from the DC magnetization and neutron scattering.