Simultaneous dHvA and SdH studies of α-(BEDT-TTF)2TlHg(SeCN)4

Utilizing cantilever magnetometry, the dHvA and SdH effects are measured simultaneously in magnetic fields to 17T and temperatures to 0.06K: In addition to high frequency oscillations (Fhigh=648T), we have detected a slow oscillation (Fslow=46T) orbit in the “Tl/Se” salt at ambient pressure in both measurements. The angular dependence of both frequencies can be well fit by F/cosθ, indicating the cylindrical nature of their Fermi surfaces. A spin-zero effect at θ=±43 °, where oscillations at the fundamental frequency vanish, was observed in the angular dependence of the 648T oscillation amplitude and in the AMRO. The absolute amplitude of the magnetization oscillation is measured and amounts to a maximum of μ0M ≊ 1.4×10−4 T at H=17T and T=60mK.