  We have measured the evolution of the tunneling density of states (DOS) in
superconductor/ferromagnet (S/F) bilayers with increasing F-layer thickness,
where F in our experiment is the strong ferromagnet Ni. As a function of
increasing Ni thickness, we detect multiple oscillations in the DOS at the
Fermi energy from differential conductance measurements. The features in the
DOS associated with the proximity effect change from normal to inverted twice
as the Ni thickness increases from 1 to 5 nm.
