Putative quantum criticality in the (Cr90Ir10)100-yVy alloy system

Abstract

Quantum criticality (QC) in spin-density-wave antiferromagnetic Cr and Cr alloy systems is a topic of current interest. In the present study, V was used as a tuning parameter to drive the Néel transition temperature (TN) of the (Cr90Ir10)100−yVy alloy series with 0 ≤ y ≤ 14.3 to zero and search for effects of QC in the process. The magnetic properties and possible QC behaviour (QCB) in this alloy system were investigated through electrical resistivity (ρ), specific heat (Cp), and susceptibility (χ) measurements as a function of temperature (T), indicating that TN is suppressed to zero at a critical concentration yc ≈ 9. The Sommerfeld coefficient (γ) is considered a key indicator of QCB and a peak is observed in γ(y) at yc on decreasing y through this concentration, followed by a sharp decreasing trend. This behaviour is reminiscent of that observed for γ of the prototypical Cr100−xVx QC system and allows for the classification of yc in the (Cr90Ir10)100−yVy alloy system as a possible QC point. Financial support from the NRF (Grant 80928 and 80626) and UJ is acknowledged.