Intermixing of ordinary and anomalous Hall effect in SrRuO3

The Hall effect resistivity ρxy of high-quality films of the itinerant ferromagnet SrRuO3 was measured at low temperatures. SrRuO3 films have large uniaxial magnetocrystalline anisotropy, and in the relevant temperature range the easy axis is 30 degrees from the film normal. We measure changes in ρxy associated with changes in the orientation of the magnetization (M) for the same applied magnetic field B [Δρxy(B,ΔM)], and we find that with increasing B, Δρxy(B,ΔM) changes its sign and its magnitude becomes more than an order of magnitude larger than the remanent (spontaneous) anomalous Hall effect. Furthermore, it appears that ρxy cannot be described as a sum of a term that depends on B and a term that depends on M, that is, the ordinary Hall effect and the anomalous Hall effect are effectively intermixed. We address qualitatively a possible link between the observed behavior of ρxy and the predicted existence of Weyl nodes in SrRuO3.