Interfacial control of magnetism and electron transport in nonisostructural SrRuO$_3$/SrCuO$_2$ heterostructure

Abstract

Heterointerfaces between structurally dissimilar oxides provide a platform to exploit the interfacial mismatch in the lattice and electronic degrees of freedom to realize emergent functionalities and tunable physical properties with potential applications in oxide electronics. Here, we investigate the magnetic and electronic transport properties of symmetry-mismatched SrRuO$_3$ (SRO)/SrCuO$_2$ (SCO) heterostructure, in which a 4-nm-thick itinerant ferromagnetic metal SRO is interfaced with a planar-type antiferromagnetic insulator SCO, in comparison with a reference SRO (4 nm) film. While both the bare SRO and SRO/SCO bilayer exhibit perpendicular magnetic anisotropy (PMA), the SRO/SCO bilayer shows a pronounced enhancement in the saturation magnetization (M$_S$ $\approx$ 2.7 $μ_B$/Ru) and effective anisotropy constant (K$_{\mathrm{eff}}$ $\approx$ 2.13 $\times$ 10$^6$ erg/cc) relative to the bare SRO film (M$_S$ $\approx$ 1.3 $μ_B$/Ru and K$_{\mathrm{eff}}$ $\approx$ 5.25 $\times$ 10$^5$ erg/cc). Interestingly, the low-temperature resistivity upturn below 5 K arising from disorder-induced quantum corrections in bare SRO is strongly suppressed in SRO/SCO, and it exhibits Fermi-liquid-like transport ($ρ\propto T^2$) down to 2 K. Analysis of the anomalous Hall effect (AHE) reveals dominant intrinsic Berry-curvature driven electron transport in both samples, with enhanced intrinsic and skew-scattering contributions in the SRO/SCO bilayer, indicating the critical role of the interface in modifying the electronic band structure near the Fermi level. Our results demonstrate that the interface acts as an effective control knob, concurrently enhancing the magnetization, PMA, and intrinsic scattering contribution to the AHE in the SRO/SCO heterostructure, while suppressing the disorder-driven quantum corrections to transport behavior observed in the bare SRO film.