We report the synthesis of Ca$_2$RuO$_4$ thin films on NdCaAlO$_{4}$ (110), LaAlO$_3$ (100) and LaSrAlO$_4$ (001) substrates and show that epitaxial strain induces a transition from the Mott-insulating phase of bulk Ca$_2$RuO$_4$ into a metallic phase. Magnetometry and spin-polarized neutron reflectometry reveal a low-temperature, small-moment ferromagnetic state in metallic Ca$_2$RuO$_4$ films.
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