  We report on the observation of a supercurrent through the half metallic
ferromagnet CrO$_2$ grown on hexagonal Al$_2$O$_3$ (sapphire). The current was
observed to flow over a distance of 700 nm between two superconducting
amorphous Mo$_{70}$Ge$_{30}$ electrodes which were deposited on the CrO$_2$
film. The critical current $I_c$ increases as function of decreasing
temperature. Upon applying an in-plane magnetic field, $I_c$ goes through a
maximum at the rather high field of 80 mT. We believe this to be a long range
proximity effect in the ferromagnet, carried by odd-frequency pairing
correlations.
