Structural, Magnetic, and Magnetocaloric Properties of La0.67Sr0.33−xKxMn0.95Ni0.05O3 Manganites (x = 0.10, 0.125, and 0.15): A-site Doping.

Polycrystalline powder samples of La0.67Sr0.33−xKxMn0.95Ni0.05O3 (x = 0.1, 0.125, 0.15) (LSKMNO) were prepared using the sol–gel method (S-G) in this study. The influence of K+ doping was systematically investigated on the lattice structure, morphology, and magnetic and magnetocaloric effect (MCE) of LSKMNO. Through the X-ray diffraction (XRD) to confirm the rhombohedral structure of LSKMNO. The magnetic results showed that the Curie temperature (TC) and the maximum magnetic entropy change ( - Δ S M max ) increase with the K+ doping for LSKMNO. The TC and - Δ S M max for LSKMNO (x = 0.15) were 319 K and 3.59 J/(kg·K) when the external magnetic field (H) was 5 T, respectively. Arrott curve and normalized magnetic entropy curve ( Δ S M / Δ S M max - θ ) are plotted to prove that LSKMNO undergoes a second order magnetic phase transition at the TC attachment. [ABSTRACT FROM AUTHOR]