Magnetic and Critical Properties of Cr1/3NbS1.86 with TC = 56 K

Abstract

The magnetic and critical properties of a TeBr‐transported CrNbS single crystal using magnetic susceptibility χ(T) and isothermal magnetization M(H) measurements are studied. A paramagnetic‐to‐ferromagnetic phase transition temperature (T C) is determined to be 56 K from χ(T) and an Arrott–Noakes’ plot. At high temperatures (T ≥ 85 K), χ(T) is well captured by the Curie–Weiss law and the effective magnetic moment is derived as P eff = 3.77 μ B per Cr. The signature of helical and chiral soliton spin structures is absent, as inferred from the (H, 2 K) data. The spontaneous magnetic moment P = 1.66 μ B per Cr compared with P eff, leading to the Rhodes–Wohlfarth ratio to be 1.75, is rather small, suggesting a slightly itinerant magnetism. However, the spin‐wave (SW) model describes the temperature‐dependent magnetization better than the single‐particle (SP) model. Further, analysis of the critical exponent yields β = 0.3852(1) and γ = 1.3575(4), which are close to the theoretical prediction of the 3D Heisenberg model and therefore suggests dominant short‐range ferromagnetic interactions. Finally, the deviation of the critical exponents from the theoretical model and the violation of Widom scaling law is discussed.