Abstract
We report improvement in the magnetocaloric properties of Ce-doped lanthanum manganites. Polycrystalline La0.7 - xCexSr0.30MnO3 (0 <= x >= 0.3) samples were prepared using the conventional solid-state reaction method with phase purity and structure confirmed using X-ray diffraction. Temperature dependent magnetization measurements and Arrott analysis reveal second order ferromagnetic transition in parent sample and as well as in doped sample with Curie temperature decreasing progressively with increasing Ce-concentration from similar to 370 K for x=0.0 to 310 K for x=0.30. Magnetic entropy change (Delta S-M) was calculated by applying the thermodynamic Maxwell equation to a series of isothermal field dependent magnetization curves. A large Delta S-M associated with the ferromagnetic paramagnetic transition in La0.7 - xCexSr0.30MnO3 samples has been observed. The value of Delta S-M was found to increase with Ce-doping up to x=0.15 and the highest value of 2.12 J kg(-1) K-1 (at Delta H=2 T) was observed for La0.55Ce0.15Sr0.30MnO3 sample near the Curie temperature of 356 K. Also, improved relative cooling power of 122 J kg(-1) was observed for the same sample. Due to the large magnetic entropy change and high Curie temperature, the La0.55Ce0.15Sr0.30MnO3 sample is suggested to be used as potential magnetic refrigerants for magnetic refrigeration technology above room temperature. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.