de Haas-van Alphen effect, magnetic transitions, and specific heat in the heavy-fermion system UCd11

We have used high pulsed magnetic fields to 50 T to observe de Haas-van Alp hen oscillations in the heavy fermion antiferromagnet UCd11, which has a st rongly enhanced value of the electronic specific-heat coefficient (gamma = 803 mJ/mol K-2). The low-temperature magnetization shows the existence of t wo magnetic phase transitions. The presence of quantum oscillations above t he first transition indicates that UCd11 has a coherent Fermi liquid, altho ugh there is little or no change in the Fermi-surface topology on passing t hrough the second transition.