Sensitivity to Disorder of the Metallic State in the Ruthenates

We report the results of transport measurements on SrRuO₃, Sr₃Ru₂O₇, and CaRuO₃. In SrRuO₃ and Sr₃Ru₂O₇, our findings are consistent with the predictions of Fermi liquid theory, in contrast to previous reports based on samples with much shorter mean free paths. In CaRuO₃, however, a T1.5 power law is seen in the resistivity in the high purity samples studied here. Our work gives concrete evidence that even the metallic state of the ruthenates is highly sensitive to disorder.