  We report measurements of quantum oscillations detected in the putative
nematic phase of Sr3Ru2O7. Significant improvements in sample purity enabled
the resolution of small amplitude dHvA oscillations between two first order
metamagnetic transitions delimiting the phase. Two distinct frequencies were
observed, and their amplitudes follow the normal Lifshitz-Kosevich profile. The
Fermi surface sheets seem to correspond to a subset of those detected outside
the phase. Variations of the dHvA frequencies are explained in terms of a
chemical potential shift produced by reaching a peak in the density of states,
and an anomalous field dependence of the oscillatory amplitude provides
information on domains.
