SIMULTANEOUS DHVA AND SDH STUDIES OF ALPHA-(BEDT-TTF)(2)TLHG(SECN)(4)

Utilizing cantilever magnetometry, the dHvA and SdH effects are measur ed simultaneously in magnetic fields to 17T and temperatures to 0.06K. In addition to high frequency oscillations (F-high=648T), we have det ected a slow oscillation (F-show=46T) orbit in the ''Tl/Se'' salt at a mbient pressure in both measurements. The angular dependence of both f requencies can be well fit by F/cos theta, indicating the cylindrical nature of their Fermi surfaces. A spin-zero effect at theta=+/-43 degr ees, where oscillations at the fundamental frequency vanish, was obser ved 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 mu(0)M congruent to 1.4x10(-4) T at H=17T and T=60mK.