Field-sweep-rate and time dependence of transverse resistivity anomalies in ultrathin SrRuO3 films

We investigated the field-sweep-rate and time dependence of the transverse resistivity anomalies in ultrathin $\mathrm{SrRu}{\mathrm{O}}₃$ epitaxial thin films the behaviors of which resemble what has been claimed to be the topological Hall effect. We find that the magnitudes of the anomalies are independent of the field sweep rate, while the magnetic field at which the anomalies appear $({H}_{\mathrm{hump}})$ and the coercive field $({H}_c)$ exhibit identical sweep-rate dependence. We also show that the transverse resistivity under a fixed external magnetic field exhibits transient behavior, eventually (\ensuremath{\approx}5000 s) approximating the value of the anomalous Hall resistivity that is obtained after the magnetization reversal processes are completed. These results indicate that ${H}_c$ is inhomogeneous within the films and activation energies of the magnetization reversal at ${H}_{\mathrm{hump}}$ and ${H}_c$ are identical. The observed field-sweep-rate and time dependence of the transverse resistivity anomalies can be understood in the framework of conventional magnetic switching dynamics, and topological interpretation would not be necessarily taken into account. Our results are in line with a model in which inhomogeneity of ${H}_c$ and anomalous Hall resistivity are responsible for the transverse resistivity anomalies in $\mathrm{SrRu}{\mathrm{O}}₃$.