De Haas-van Alphen oscillation in both the normal and superconducting mixed states of UPd2Al3

We succeeded in growing a high-quality single crystal of the heavy fermion superconductor UPd2Al3 and observed the de Haas-van Alphen (dHvA) oscillation in both the normal and superconducting mixed states. The dHvA frequency, which is proportional to a maximum cross-sectional area of the electron Fermi surface labelled alpha, does not change in magnitude between the normal and mixed states, while the cyclotron mass of 5.7 m(0) in the normal state is reduced to 3.5 m(0) at 0.7 H-c2, and the corresponding Dingle temperature of 0.20 K in the normal state is increased to 0.39 It at 0.7 H-c2. Here, H-c2 of 39 kOe is the upper critical field along the [0001] direction in the hexagonal structure.