Magnetic resistivity in ${\mathrm{SrRuO}}_3$ and the ferromagnetic phase transition

We measured the resistivity of the itinerant ferromagnet ${\mathrm{SrRuO}}_3$ as a function of temperature $(120\mathrm{}\mathrm{K}<T<\mathrm{}180\mathrm{}$ K) and magnetic field $(0<H<\mathrm{}10\mathrm{}$ kOe) in the vicinity of the ferromagnetic phase transition ${(T}_c\sim 150$ K). We find that the magnetic resistivity ${\rho }_m$ is related to the magnetization M by ${\rho }_m\mathrm{}\left(M\right)={\rho }_m\mathrm{}\left(0\right)\mathrm{}-{\mathrm{aM}}^2$ over a wide range of M. From the analysis of the resistivity data we determine the critical parameters of the phase transition $\beta =0.34\mathrm{}\pm 0.02,$ $\gamma =1.14\mathrm{}\pm 0.07$ below $T_c,$ $\gamma =1.17\mathrm{}\pm 0.14$ above $T_c,$ $C^{+}{/C}^{-}\sim 4.$ Here $\beta$ and $\gamma$ are the critical exponents of the spontaneous magnetization and the susceptibility, respectively, and $C^{+}{/C}^{-}$ is the amplitude ratio of the susceptibility. Our results are supported by a collapse of the magnetoresistance data on a single curve when an approriate scaling function is used.