Magnetic interactions in Pr_0.67Sr_0.33MnO₃ nanoparticles: mean-field theory vs. experiments

This study presents the modelling of magnetocaloric effect of Pr_0.67Sr_0.33MnO₃ nanoparticles by using the mean-field theory (MFT). Theoretical calculations were used around the Curie temperature (T_C) to simulate the temperature dependence of magnetic entropy change under several applied magnetic fields. The obtained results were compared with experimental data computed using the Maxwell relation. Discrepancy between the two methods confirm the invalidity of MFT for modelling the magnetocaloric properties of Pr_0.67Sr_0.33MnO₃ nanoparticles. This invalidity suggests the presence of critical fluctuations near the T_C, which can be attributed to the presence of disordered surface and/or magnetic frustration, and highlights the limitation of the used model.