Comparative analysis of magnetocaloric effect in La_0.67-xEu_xBa_0.33Mn_0.85Fe_0.15O₃ (x = 0 and 0.1) polycrystalline manganites: experimental vs. theoretical determination

This research study explores the magnetic and magnetocaloric properties of La_0.67-xEu_xBa_0.33Mn_0.85Fe_0.15O₃ (x = 0 and 0.1) magnetic compounds elaborated using the Sol–Gel method, based on a phenomenological approach proposed by Mahmoud Aly Hamad. The studied compounds exhibit a second-order ferromagnetic (FM) to paramagnetic (PM) transition with increasing temperature. A correlation between the experimental measurements and the theoretical analysis is established. Indeed, the value of the magnetocaloric effect was determined from the theoretical model based on magnetization as a function of temperature at several magnetic fields. Under an applied magnetic field of 5T, the absolute values of the maximum magnetic entropy change are evaluated at 0.92 and 0.60 J kg⁻¹ K⁻¹ for x = 0 and 0.1 respectively. This reduction may be attributed to a Curie temperature distribution implying also a decrease in the relative cooling power (RCP). The RCP and the specific heat capacity values are also estimated thanks to this model. The results predicted by this model allow us to propose these compounds as promising candidates for magnetic refrigeration.