Electrical transport properties of single-crystal Sr3Ru2O7: The possible existence of an antiferromagnetic instability at low temperatures - art. no.174435

We report the results of Hall coefficient R-H and magnetoresistance (MR) me asurements on single crystalline samples of Sr3Ru2O7 grown by the floating zone method. RH was found to be positive over the entire temperature range studied (0.3-300 K). Its temperature (T) dependence follows closely that of the magnetic susceptibility including a maximum at a characteristic temper ature T* = 17 K. We show that RH can be decomposed into normal and anomalou s parts as in the case of skew scattering in heavy-fermion compounds and fe rromagnetic metals. This, together with the observation that the longitudin al MR is greater than the transverse MR at the same magnetic field and temp erature, suggests that magnetic fluctuations dominate the electrical transp ort properties in Sr3Ru2O7. We found a crossover in the sign of the MR at T *, from positive to negative as the temperature increased, for both the tra nsverse and the longitudinal configurations. In addition, a nonmonotonic be havior in the field dependence of the MR was found at low temperatures. The se observations suggest that the magnetic correlations in Sr3Ru2O7 at ambie nt pressure undergo a qualitative change as the temperature is lowered. Abo ve T*, they are dominated by ferromagnetic instability. However, below T*, the system crosses over to a different behavior, controlled possibly by a c anted antiferromagnetic instability.