Electron-electron interaction and weak localization effects in badly metallicSrRuO3

Abstract

We report on the effect of light ion irradiation on the low-temperature electrical resistivity of ferromagnetic ${\mathrm{SrRuO}}_3$ thin films. Fresh samples displayed a ferromagnetic transition at $T_c\sim 160\mathrm{K},$ good metallic behavior $\left(\rho \right(300\mathrm{}\mathrm{K})\sim 400\mu \Omega \mathrm{cm},$ $d\rho /dT>\mathrm{}0\mathrm{})$ at room temperature, and the low-temperature upturn in the electrical resistivity commonly found in ${\mathrm{SrRuO}}_3.$ Badly metallic films, displaying high values of the electrical resistivity $\left(O\right(1000\mathrm{}\mu \Omega \mathrm{cm}\left)\right)$ and incipient nonmetallic behavior $(d\rho /dT<\mathrm{}0)$ at low temperature, were obtained by ${\mathrm{He}}^{+}$ irradiation. For high enough irradiation doses, these samples did not show magnetic order down to the base temperature of our experiments. The temperature dependence of the electrical conductivity of virgin and irradiated samples is discussed in terms of a weak localization contribution plus a large electron-electron interaction term. The magnitude of the $e^{-}{-e}^{-}$ contribution reflects the enhancement of strong electron correlations in ${\mathrm{SrRuO}}_3$ due to disorder.