  A multi-terminal device based on a carbon nanotube quantum dot was used at
very low tem- perature to probe a single electronic and nuclear spin embedded
in a bis-phthalocyanine Terbium (III) complex (TbPc2). A spin-valve signature
with large conductance jumps was found when two molecules were strongly coupled
to the nanotube. The application of a transverse field separated the magnetic
signal of both molecules and enabled single-shot read-out of the Terbium
nuclear spin. The Landau-Zener (LZ) quantum tunneling probability was studied
as a function of field sweep rate, establishing a good agreement with the LZ
equation and yielding the tunnel splitting \Delta. It was found that ?
increased linearly as a function of the transverse field. These studies are an
essential prerequisite for the coherent manipulation of a single nuclear spin
in TbPc2.
