Dependence of Curie-Weiss Temperature on Mn Concentration in Dilute

Abstract

We have measured the magnetic susceptibility at low temperatures (1.2–4.2 K) of a series of ZnMn alloys (20–2500 ppm Mn) and have found that χ can be represented by a Curie‐Weiss law, χ = C/(T+θ), where both C and θ vary with concentration n of Mn impurities. As a function of n, θ goes through a minimum (θmin = 0.3 K) at about n=100 ppm Mn. We interpret this minimum in θ, which is here observed for the first time in a dilute magnetic alloy system, as resulting from the competition between single‐impurity (Kondo) and impurity‐impurity (RKKY) interactions. We also report on the concentration dependence of the Curie constant C.