  SrRuO$_3$ (SRO113) is an important material for device physics particularly
as one of the best metallic oxide electrodes for ferroelectric devices. This
oxide has moderate electron correlations with novel properties including
ferromagnetic ordering, which can be utilized in future to spintronics and
superconducting spintronics devices. Recently, we observed strongly enhanced
magnetization of SRO113 thin films grown on single crystals of the spin-triplet
superconductor Sr$_2$RuO$_4$ (SRO214). To clarify the origin of such an
enhancement, we conducted systematic investigations of magnetic properties of
SRO113 films deposited on a variety of oxide substrates. We carefully
subtracted the substrate contributions and found that the enhanced 2
magnetization occurs only for SRO113/SRO214 films. We further found that
neither strain nor metallicity of the substrate plays any significant roles in
the enhancement. The X-ray magnetic circular dichroism reveals that the
substrate-induced strain does not switch the Ru4+ state from the low-spin to
high-spin states. The film-thickness dependence of the magnetization of
SRO113/SRO214 films strongly suggest that the additional magnetization arises
due to the induction of magnetic moment into the SRO214 substrate over 20-nm
depth. Our results imply new magnetic functionality that can trigger studies
searching for yet unknown physical phenomena in magnetic ruthenates.
