Analysis of the magnetization as functions of the temperature and the field close to the ferromagnetic–paramagnetic phase transition in MnCoGe1– x Si x

The critical behavior of the magnetization M as a function of temperature and ma gnetic field is analyzed using experimental data from the literature for different concentrations of the MnCoGe1–xSix alloy near the ferromagnetic–paramagnetic (FM–PM) transition. The critical exponent β of M(T) is determined using the power-law relation and the Kouvel–Fisher method. The critical exponent δ, characterizing the critical isotherm M(H), is determined using the power-law relation with the Widom scaling law. Using the Arrott–Noakes equation, the critical exponents β of M(T) and γ of the magnetic susceptibility χ(T) are determined, and then χ(T) is predicted for different concentrations x of MnCoGe1–xSix. Our values for the critical exponents (β, γ, and δ) determined from the analyses are compared with those expected by the 3D Ising ferromagnet.