Spin-density-wave effects in the (Cr98.4Al1.6)100−Mo alloy system

Abstract The possibility of quantum critical behaviour in a spin-density-wave antiferromagnetic (Cr 98.4 Al 1.6 ) 100− y Mo y alloy system is investigated through electrical resistivity, Seebeck coefficient and specific heat measurements. Magnetic resistivity anomalies associated with the Neel transition temperature are highly enhanced in the thermoelectric measurements, allowing for complementary methods in obtaining the Neel temperatures of these alloys. The results indicate a suppression of the Neel temperatures to below 2 K for alloy concentrations y ≳4.5. This aspect is strongly reflected in the y -dependence of the residual resistivity and Sommerfeld specific heat coefficient. Both parameters depict rather sharp changes, related to spin-density-wave energy gap influences, on entering the antiferromagnetic phase when y is decreased at 2 K through y c ≈4.5 on the concentration-temperature magnetic phase diagram. The behaviour of the concentration dependence of the Sommerfeld specific heat coefficient is suggestive of quantum critical behaviour in this alloy system, with a quantum critical point at y ≈ y c .