Structural Analysis and Theoretical Investigations of the Magnetocaloric Effect for La_0.7Ba_0.15Ag_0.15MnO₃ Manganite Prepared Using Sol-Gel Route

Structural analysis, magnetocaloric properties, and theoretical investigations of the magnetocaloric effect were carried out in the crystalline La_0.7Ba_0.15Ag_0.15MnO₃ manganite prepared using sol-gel route. The phase purity and structure of this sample were checked by X-ray diffraction technique and Rietveld analysis. From magnetic measurements, the ferromagnetic to paramagnetic (FM-PM) phase transition was observed around T_C = 255 K. The maximum change in magnetic entropy (∆SMmax) and relative cooling power (RCP) extracted from magnetic measurements were 3.48 J × kg-1 × K-1 and 225 J × kg-1 at an applied magnetic field of 5 T. These magnetocaloric parameters offer to the sample the possible use in the magnetic refrigeration technology. The magnetic entropy simulation by using different theories such as the Weiss molecular mean-field theory and the Landau theory shows good correlation between the theoretical values of −∆S_M(T) and the experimental ones estimated from Maxwell relation.