superlattices*

Emergent ferromagnetism has been observed at the interface of CaRuO₃ (CRO), a paramagnetic metal, and CaMnO₃ (CMO), an antiferromagnetic insulator. The leakage of itinerant CRO electrons into the CMO results in a double exchange interaction among interfacial Mn. Since CMO is a G-type antiferromagnet, films grown in (111) direction should have fully uncompensated surfaces and higher interfacial moments than compensated (001) surfaces. We demonstrate the synthesis and characterization of (111) CRO/CMO superlattices with 3 layers of CRO and 3-19 layers of CMO. To grow smooth (111) superlattices, we developed an interval pulsed laser deposition process. SQUID magnetometry measurements indicate larger interfacial Mn moments in our (111) superlattices compared to (001) superlattices. Coercive fields of the superlattice are similar, regardless of CMO thickness, and with increasing CMO thickness, the exchange bias field in the magnetization loops increases. Since CMO and CRO are isovalent, CRO/CMO systems do not exhibit a polarity mismatch across the interface, providing a model system to explore emergent ferromagnetism.