In this study, we investigate structural, magnetic, magnetocaloric and thermoelectric properties of
La0.7Sr0.3Mn1-xNixO3 compounds with 0.025 x 0.125. X-ray diffraction analysis shows the structure
transformation from the R-3c rhombohedral to the Pbnm orthorhombic structure with Ni2þ doping at x
0.075 composites. The dc thermal magnetization measurements reveal the monotonic decrease in both
Curie temperature and magnetization values with Ni2þ addition. The change in magnetic properties of
the studied system is correlated to the ferromagnetism suppression and the antiferromagnetism promotion
according to some cooperative intrinsic and extrinsic factors. Results show that Ni2þ addition
affects the magnetocaloric properties, where it shifts the maximum value of the magnetic entropy
change towards lower temperatures with relative cooling power of 88, 105, 47 J/kg for x ¼ 0.025, 0.075
and 0.125 composites, respectively. Moreover, it is observed that Ni2þ doping increases the absolute value
of Seebeck coefficient and decreases hole conduction interval.