  We report on the electrical transport properties of Nb based Josephson
junctions with Pt/Co$_{68}$B$_{32}$/Pt ferromagnetic barriers. The barriers
exhibit perpendicular magnetic anisotropy, which has the main advantage for
potential applications over magnetisation in-plane systems of not affecting the
Fraunhofer response of the junction. In addition, we report that there is no
magnetic dead layer at the Pt/Co$_{68}$B$_{32}$ interfaces, allowing us to
study barriers with ultra-thin Co$_{68}$B$_{32}$. In the junctions, we observe
that the magnitude of the critical current oscillates with increasing thickness
of the Co$_{68}$B$_{32}$ strong ferromagnetic alloy layer. The oscillations are
attributed to the ground state phase difference across the junctions being
modified from zero to $\pi$. The multiple oscillations in the thickness range
$0.2~\leqslant~d_\text{CoB}~\leqslant~1.4$~nm suggests that we have access to
the first zero-$\pi$ and $\pi$-zero phase transitions. Our results fuel the
development of low-temperature memory devices based on ferromagnetic Josephson
junctions.
