Depth-resolved profile of the interfacial ferromagnetism in CaMnO₃/CaRuO₃ superlattices.

Emergent magnetic phenomena at interfaces are crucial for advancing spintronics and magnetic storage technologies. Here, we employ advanced X-ray spectroscopic and scattering techniques to explore interfacial ferromagnetism in oxide superlattices of antiferromagnetic CaMnO₃ and paramagnetic CaRuO₃. We show that ferromagnetism extends beyond the interfacial layer into multiple CaMnO₃ unit cells with an asymmetric magnetic profile. Density functional calculations suggest this is driven by double exchange via charge transfer from Ru to Mn ions. Additionally, oxygen vacancies influence the magnetic moments at the interface, contributing to the asymmetry. These findings highlight the potential for tuning interfacial ferromagnetism through defect engineering.