Extraordinary Hall effect in SrRuO3

We have measured the Hall effect in thin films of the itinerant ferromagnet SrRuO3 as a function of temperature (1.8 K-300 K) and field (0-8 T). We find that the extraordinary Hail coefficient R-s changes sign and can be described as R(s)approximate to cT(5)+b rho(2) where T is temperature and rho is resistivity. We discuss possible interpretations of this result.