MAGNETIC QUANTUM OSCILLATIONS IN CE-BASED HEAVY-FERMION COMPOUNDS

We report on quantum oscillation studies in Ce-based heavy-fermion com pounds, in particular on the magnetic field dependence of the quasipar ticle effective mass in CeB6 at the lowest possible fields. We make us e of a new SQUID-based de Haas-van Alphen (dHvA) spectrometer, which w as developed for use in very high magnetic fields (upto 19 T) and at u ltralow temperatures (< 3 mK) for the study of heavy-fermion materials . As a result of the unprecedented sensitivity, the dHvA measurements have been extended to much lower magnetic field regimes and temperatur es than previously possible.