  Topological spin textures as an emerging class of topological matter offer a
medium for information storage and processing. The recently discovered
topological Hall effect (THE) is considered as a fingerprint for electrically
probing non-trivial spin-textures. But the origin of THE in oxides has remained
elusive. Here we report an observation of the THE in ultrathin (unit cells.
u.c.) 4d ferromagnetic SrRuO3 films grown on SrTiO3(001) substrates, which can
be attributed to the chiral ordering of spin structure (i.e., skyrmion-like) in
the single SrRuO3 layer without contacting 5d oxide SrIrO3 layer. It is
revealed that the RuO6 octahedral tilting induced by local
orthorhombic-to-tetragonal structural phase transition exists across the
SrRuO3/SrTiO3 interface, which naturally breaks the inversion symmetry. Our
theoretical calculations demonstrate that the Dzyaloshinskii-Moriya (DM)
interaction arises owing to the broken inversion symmetry and strong spin-orbit
interaction of 4d SrRuO3. This DM interaction can stabilize the N\'eel-type
magnetic skyrmions, which in turn accounts for the observed THE in transport.
The RuO6 octahedral tilting-induced DM interaction provides a pathway toward
the electrical control of the topological spin textures and resultant THE,
which is confirmed both experimentally and theoretically. Besides the
fundamental significance, the understanding of THE in oxides and its electrical
manipulation presented in this work could advance the low power cost
topological electronic and spintronic applications.
