Magnetic anisotropic pinning and symmetric breaking induced by interfacial coupling in topological-like ruthenate superlattices

Interfacial engineering enables various emergent effects such as spin reorientations and transport anisotropy. Noncollinear spin textures are essential for realizing many emergent quantum transport phenomena. However, driving such spin structures requires precise control of the interfacial magnetic coupling in complex oxide heterostructures. Here, by utilizing competing exchange interactions at the interface between ferromagnetic metal SrRuO3 and ferromagnetic insulator LaCoO3, we discovered a noncollinear spin configuration in SrRuO3 sublayers. Magnetic stripes were induced by out-of-plane rather than in-plane magnetic fields, indicating strong anisotropy pinning in our superlattices. The observed magneto-transport anisotropy is well explained by our proposed spin configurations, accounting for contributions from both bulk and interface of the SrRuO3 layers. More interestingly, magnetic skymionic textures were absent even at high magnetic fields. The interfacial exchange interaction overwhelms the Dzyaloshinskii-Moriya interaction (DMI) that stabilizes skyrmions, featuring a higher exchange coupling energy than that for the topological spin textures. Our work highlights the potential of interfacial engineering in tuning the spintronic properties by designing proper interfacial interactions.