Non-Fermi Liquid Behavior and Topological Hall Effect in SrRuO₃

Here we report on the non-Fermi liquid behavior in high quality single crystal SrRuO₃ thin films grown by hybrid molecular beam epitaxy. SrRuO₃ thin films show metallic behavior down to helium liquid temperature. All samples show negative longitudinal magnetoresistance with a hysteresis appearing below 130 K. Furthermore, field cooling magnetization measurement confirms a drastic enhancement in magnetic signal at the same temperature. The resistivity data from 2 K to 40 K, using the general expression R(T)=R₀+ATⁿ for transport, resolves n=2 at low temperature (2 K) and n=1.5 at high temperature (40 K) with a smooth transition in between. Sweeping out-of-plane magnetic field (0-8 T) at different temperatures shows a drop in “n” and, concurrently, an enhancement in temperature coefficient at ~ 3 T. The temperature coefficient is directly proportional to carrier mass and the enhancement in “A” hints that carriers are getting heavier. An anomalous Hall effect (AHE) roughly ten times stronger that ordinary Hall effect (OHE) dominates the Hall signal at low fields. Finally, a topological Hall effect (THE) feature can be resolved superimposed on the AHE and OHE signals.