Tuning Ferromagnetism and Perpendicular Magnetic Anisotropy in Manganite–Iridate Superlattices via Intralayer Coupling

Interfaces between 3d and 5d transition metal oxides exhibit exotic phenomena, such as emergent perpendicular magnetic anisotropy (PMA). While interlayer exchange coupling between these cations has been extensively studied, intralayer interactions remain unexplored. Here, we construct a new type of superlattice comprising a La_0.7Sr_0.3MnO₃ monolayer and a mixed La_0.7Sr_0.3MnO₃-SrIrO₃ monolayer in each repetition (i.e., [(LSMO)_1+x/(SIO)_1-x]_N), to artificially introduce extra Mn-O-Ir exchange interactions within the atomic plane. The Curie temperature gradually increases with x, whereas the PMA strength exhibits a nonmonotonic change with a maximum at x = 0.5, which could be attributed to enhanced single-ion anisotropy and increased magnetic moments of Ir ions as revealed by first-principles calculations. Moreover, this strategy leads to enhanced magnetoresistance and a sign-change of anomalous Hall resistivity as compared to the superlattice with sharp interfaces (x = 0). Our findings demonstrate an alternative route via tuning intralayer coupling to engineer interface-driven emergent properties for next-generation all-oxide spintronic devices.