This work presents a comprehensive mean-field theory (MFT) analysis of the magnetic and thermodynamic behavior of La 0. 6 Dy 0. 1 Sr 0. 3 Mn -x Bi x O 3 \ ( (x = 0, 0. 01, 0. 03, 0. 1) \) manganites. The isothermal magnetizations \ (M (H, T) \) were modeled using the Brillouin function incorporating an effective exchange field which is found to vary linearly with magnetization across all compositions. The estimated critical exponent \ (\) and spontaneous magnetization determined via both magnetocaloric entropy and Arrott plots, align closely with mean-field predictions. The theoretical \ (M (H, T) \) and magnetic entropy change curves, calculated via MFT, show good agreement with experimental measurements, especially at high fields. However, deviations at low fields and near criticality suggest limitations of the MFT approach due to local inhomogeneities and critical fluctuations.
Khadhraoui et al. (Mon,) studied this question.