Proton-controlled Dzyaloshinskii-Moriya interaction and topological Hall effect in hydrogenated strontium ruthenate.

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The Topological Hall effect (THE) is a fascinating physical phenomenon related to topological spin textures, serving as a powerful electrical probe for detecting and understanding these unconventional magnetic orders and skyrmions. Recently, the THE has been observed in strontium ruthenate (SrRuO3, SRO) thin films and its heterostructures, which originates from the disruption of interfacial inversion symmetry and Dzyaloshinskii-Moriya interaction (DMI). Here, we demonstrate a practically pure proton doping effect for controlling the DMI and THE in the SRO epitaxial films using the Pt electrode-assisted hydrogenation method. The hydrogenation process can realize approximately 0.8 protons per unit cell incorporating into the SRO films (thickness >10 nm) without causing significant lattice expansion and oxygen vacancies. Consistent with first-principles calculations, atomic-scale observations confirm that the proton doping induces a vertical displacement of Ru and O atoms in hydrogenated SRO (H-SRO), which remarkably enhances the DMI and leads to the emergence of the THE. More importantly, the proton doping drives two distinct topological signals in the ferromagnetic H-SRO, exhibiting greater THE values but no occurrence of structural transition. Our study has demonstrated that catalysis-assisted hydrogenation is an efficient strategy for manipulating the emerging THE and magnetic textures in correlated oxide thin films.