Hall effect in the two-dimensional metal Sr2RuO4

We report a detailed study of the Hall effect in Sr2RuO4, the first layered perovskite superconductor which does not contain copper (T-c congruent to 1 K). The Hall coefficient (R(H)) was measured at temperatures between 20 mK and 300 K, and an unusual dependence of R(H) on the applied magnetic field was observed. R(H) has a strong temperature dependence below 25 K, but below 1 K it saturates at a value of -1.15x10(-10) m(3)/C. The Fermi surface of Sr2RuO4 is known from quantum oscillation measurements, and since it is nearly two dimensional, it is possible to derive a simple expression for R(H) using methods developed by Ong [Phys. Rev. B 43, 193 (1991)]. We show that if the mean free path, l, is assumed to be isotropic at low temperatures, it is possible to make an accurate quantitative calculation of R(H) on the basis of the known Fermi surface parameters.