Effect of Zn substitution on magnetic properties and magnetic entropy change in La_0.7Ba_0.25Nd_0.05Mn_1-xZn_xO₃ (x = 0.03 and 0.05) synthesized by using sol-gel method

This investigation explored the structural, magnetic, and magnetic entropy change characteristics of La_0.7Ba_0.25Nd_0.05Mn_1-xZn_xO₃ (x = 0.03 and 0.05) synthesized through the sol-gel method. The structural analysis revealed the crystallization of both samples in a Rhombohedral structure with the R-3c space group. The examination of magnetic properties indicated a suppression in magnetic behavior, with the ferromagnetic-paramagnetic transition temperature (T_C) decreasing from 285 K to approximately 260 K with an increase in Zn content (x) from 0.03 to 0.05, respectively. The maximum value of magnetic entropy change (−ΔS_M) under an applied magnetic field of 50 kOe was determined to be 3.96 J/kg·K for x = 0.03 and 2.27 J/kg·K for x = 0.05. Analysis of Arrot plots and the universal curve of magnetic entropy change confirmed that the ferromagnetic-paramagnetic phase transition observed in both samples exhibits a second-order phase transition (SOPT) transformation.