Figure 10

AC susceptibility measurements with x = 0.875. (a) The temperature dependence of the real part of the AC susceptibility (χ′(T)) for frequencies ranging from 10 to 10,000 Hz for Co _x Fe_1−xS₂, where x = 0.875. (b) Inverse susceptibility versus temperature and its linear fit (gray and pink lines). Frequency dependence of \({T}_{{\rm{\max }}}^{AC}\) and its fit using the (c) Néel-Arrhenius model, (d) Vogel-Fulcher model and (e) the critical slowing down model.