High magnetic field study ofCePd2Si2

Abstract

The de Haas--van Alphen (dHvA) effect in the heavy fermion system ${\mathrm{CePd}}_{2}{\mathrm{Si}}_{2}$ was studied by magnetic torque measurements in magnetic fields up to 28 T at low temperature. A clear magnetic torque anomaly observed at ${B}_{m}\ensuremath{\sim}10\mathrm{T}$ applied along the crystallographic a axis indicates a metamagnetic transition. The transition also manifests itself by a sharp drop of the magnetoresistance at low temperature. The dHvA oscillations observed above the transition reveal six different frequencies in the basal plane with the corresponding effective masses from ${6m}_{e}$ to ${23m}_{e}.$ Comparison of the angular dependence of the dHvA frequencies with the theoretical band-structure calculations implies that the $4f$ electrons are itinerant rather than localized inside a magnetically ordered state. One frequency is split into two close satellites, which most likely originate from the up and down spin bands, whose effective masses differ by a factor of 2. The spin splitting gives rise to an apparent anomalous field dependence of the effective mass obtained from the experiment.