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

摘要

The Pechini sol-gel and solid-state methods were used to prepare La0.7Sr0.3Mn0.95Ni0.05O3 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 delta S-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 delta S-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.

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