High magnetic field study of CePd2Si2

Abstract

The de Haas-van Alphen ͑dHvA͒ effect in the heavy fermion system CePd 2 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 ϳ10 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 4 f 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.