Rashba Coupling Driven Giant Topological Hall Effect in Epitaxial Py/LSMO-Based Heterostructures

The emergence of novel physical phenomena at interfaces between complex oxide materials continues to attract significant research interest due to its fundamental importance and technological potential. In this work, we demonstrate a remarkably large topological Hall resistivity of approximately 2.8 μΩ·cm at room temperature in an epitaxial Ni₈₀Fe₂₀ (Py)/La₀.₆₅Sr₀.₃₅MnO₃ (LSMO) thin-film heterostructure. This giant topological Hall response, far exceeding that of individual Py and LSMO films, originates from the synergistic interplay between the ferromagnetic ordering in LSMO and the interfacial Rashba-type spin–orbit coupling arising from broken inversion symmetry at the Py/LSMO interface.

Furthermore, the insertion of a ferroelectric BaTiO₃ (BTO) spacer layer between Py and LSMO enhances the interfacial electric-field control, leading to an even stronger topological Hall signal compared to the single-layer Py film. Magnetic force microscopy (MFM) reveals skyrmion-like spin textures, providing microscopic evidence for the topological nature of the Hall effect in these heterostructures. Complementary theoretical calculations of skyrmion lattice formation confirm that Rashba-driven chiral spin textures can quantitatively explain the observed behavior.

Our findings establish Py/LSMO and Py/BTO/LSMO heterostructures as promising candidates for next-generation oxide-based spintronic devices, where interfacial engineering and spin–orbit coupling can be utilized to stabilize and manipulate topological spin structures at room temperature.