Giant generic topological Hall resistivity of MnSi under pressure

We report detailed low temperature magnetotransport and magnetization measurements in MnSi under pressures up to $\sim 12\mathrm{k}\mathrm{b}\mathrm{a}\mathrm{r}$. Tracking the role of sample quality, pressure transmitter, and field and temperature history allows us to link the emergence of a giant topological Hall resistivity $\sim 50\mathrm{n}\mathrm{\Omega }\mathrm{c}\mathrm{m}$ to the skyrmion lattice phase at ambient pressure. We show that the remarkably large size of the topological Hall resistivity in the zero-temperature limit must be generic. We discuss various mechanisms which can lead to the much smaller signal at elevated temperatures observed at ambient pressure.