New hints on the origin of quantum criticality in CeCoIn5: A Hall effect study

Abstract

We report Hall Effect measurements under pressure in the normal state of CeCoIn5, from 60 to 355 mK and for fields exceeding the superconducting upper critical field Hc 2, with the field oriented parallel to [0 0 1]. At low pressures, the field dependence of the Hall coefficient exhibits a scaling consistent with the one reported in the normal state at higher temperatures, but at odds with the Δ H / T scaling expected near a field tuned quantum critical point. The breakdown of this scaling at higher pressures, concomitant with the suppression of spin fluctuations, suggests that it is a hallmark of the spin fluctuations.