Critical behavior in the antiperovskite Mn3CuN at ferromagnetic to paramagnetic phase transition

Abstract

We have investigated the critical behavior of Mn3CuN in the ferromagnetic (FM) to paramagnetic (PM) transition. Critical behavior of Mn3CuN can be divided into two stages around Curie temperature (TC): i) ZI (T>TC) and ii) ZII (T<TC). By using various methods, including modified Arrott plot, Kouvel–Fisher (KF) method, and critical isotherm analysis, reliable critical exponents β, γ and δ are approached. With these critical exponents, magnetization–field–temperature (M–H–T) data below and above TC collapse into two universal branches in the asymptotic critical region following the scaling equation. It was found that in ZI mean-field model occupies a predominate position, while for ZII, J(r)∼r−4.8 lies between the theoretical values of 3D Heisenberg model and the mean-field model, indicating that the competition between Mn–Mn and Mn–N bonds should be responsible for the exchange interaction.