  A combination of spectroscopic probes was used to develop a detailed
experimental description of the transport and magnetic properties of
superlattices composed of the paramagnetic metal CaRuO$_3$ and the
antiferromagnetic insulator CaMnO$_3$. The charge carrier density and Ru
valence state in the superlattices are not significantly different from those
of bulk CaRuO$_3$. The small charge transfer across the interface implied by
these observations confirms predictions derived from density functional
calculations. However, a ferromagnetic polarization due to canted Mn spins
penetrates 3-4 unit cells into CaMnO$_3$, far exceeding the corresponding
predictions. The discrepancy may indicate the formation of magnetic polarons at
the interface.
