Experimental Study on the Magnetic and Magnetocaloric Properties of Two Perovskite Compositions, La_0.7Nd_0.1Sr_0.2MnO₃ and La_0.7Nd_0.1Sr_0.2Mn_0.96In_0.04O₃, and Their Effect on Chemical Stability in Memory Devices

The chemical stability effect was investigated using two perovskite compositions, La_0.7Nd_0.1Sr_0.2MnO₃ and La_0.7Nd_0.1Sr_0.2Mn_0.96In_0.04O₃. Synthesis of these perovskites was carried out by the sol–gel method. X-ray powder diffraction study, coupled with Rietveld refinement, revealed a rhombohedral structure with the R \(\overline{3 }\) $\overline{3}$ c space group. The magnetic investigation showed that both compositions exhibit a second-order phase transition. La_0.7Nd_0.1Sr_0.2MnO₃ has a Curie temperature T_C of 290 K and maximum magnetic entropy change value of 4.79 J kg⁻¹ K⁻¹, while La_0.7Nd_0.1Sr_0.2Mn_0.96In_0.04O₃ has a Curie temperature T_C of 277 K and maximum magnetic entropy change value of 6.2 J kg⁻¹ K⁻¹. The critical properties of these compositions were analyzed and found to obey the mean-field model for La_0.7Nd_0.1Sr_0.2 Mn_0.96In_0.04O₃ and the Heisenberg model for La_0.7Nd_0.1Sr_0.2MnO₃.