De Haas-van Alphen Oscillation in Both the Normal and Superconducting Mixed States of UPd₂Al₃

Abstract

We succeeded in growing a high-quality single crystal of the heavyfermion 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 areaof the electron Fermi surface labelled α, does not change inmagnitude between the normal and mixed states, while the cyclotron mass of5.7, m₀ in the normal state is reduced to 3.5, m₀ at 0.7, H_c2, and the corresponding Dingle temperature of 0.20, K in the normalstate is increased to 0.39, K at 0.7, H_c2. Here, H_c2 of 39, kOe is the upper critical field along the [0001]direction in the hexagonal structure.