Favourable modification of magnetic and magnetocaloric properties of La0.5Sr0.5CoO3 upon Ba substitution

The influence of Ba substitution (5-15%) on magnetic and magnetocaloric properties of La0.5Sr0.5CoO3 ceramics has been investigated in this study. Hysteresis loops confirm the ferromagnetic nature of the Ba-substituted cobaltites. The magnetic entropy change peaks,-?S- M(max) , in La-0.5(Sr1-xBax)(0.5)CoO3 are observed at their respective T-C values of 241, 239 and 237 K for x = 0.05, 0.1 and 0.15, respectively. However, the position of-?S- M(max) shifts to a slightly higher temperature for an applied field above 1 T, which is accounted for by the short-range ferromagnetic correlations existing above T-C. The values of--?S- M(max) for x = 0.05, 0.1 and 0.15 corresponding to a field change of 5 T are recorded as 2.46, 2.51 and 2.42 J kg(-1) K-1, respectively. A remarkable enhancement in relative cooling power is observed with Ba substitution becoming highest at 141.38 J kg(-1) for x = 0.15. All these attributes of the studied materials suggest the feasibility to find applications as magnetic refrigerants.