Physical Explanation of Magnetic and Magnetocaloric Effects of La0.7Sr0.3Mn0.95Ni0.05O3 in Different Synthesis Methods.

The Pechini sol–gel and solid-state methods were used to prepare La_0.7Sr_0.3Mn_0.95Ni_0.05O₃ specimens for analysis of their microscopic morphology, magnetic and magnetocaloric effect properties. The results showed that the average particle size of the sample made by the Pechini sol–gel method was 127.7 nm, smaller than 444.6 nm using the solid-state method. The Curie temperature (T_C) of Pechini sol–gel (S–G) and solid-state (S-S) samples was 321.7 K and 334 K; the ΔS_M was 4.15 J kg⁻¹ K⁻¹ and 3.11 J kg⁻¹ K⁻¹ under an applied magnetic field of 5 T. The samples were all second-order phase transition materials, indicating that the phase transition order was independent of the synthesis method. The T_C of the S–G sample shifted to a lower temperature and the ΔS_M was significant, which is desired for magnetic refrigeration. This shows that the synthesis path strongly impacts the morphology and physical properties, explaining the physical mechanism of these property changes in detail. [ABSTRACT FROM AUTHOR]