Magnetocaloric Properties in La0.5Ca0.45K0.05MnO3, Pr0.5Sr0.45K0.05MnO3, and Nd0.5Sr0.45K0.05MnO3 Manganites

Abstract

In this paper, we report the result of the influence of 5 % K doping upon the magnetic and magnetocaloric properties of La 0.5 Ca 0.45 K 0.05 MnO 3 , Pr 0.5 Sr 0.45 K 0.05 MnO 3 , and Nd 0.5 Sr 0.45 K 0.05 MnO 3 perovskite manganites. Our samples have been synthesized by the conventional solid-state reaction at high temperature. X-ray diffraction analysis using the Rietveld refinement show that all our synthesized samples are single phase and crystallize in the orthorhombic structure with Pbnm space group for all the compounds. Magnetization measurements versus temperature in a magnetic applied field of 50 mT indicate that all our investigated samples display a paramagnetic-ferromagnetic transition with decreasing temperature. The Curie temperatures are found to be 295.2, 296.4, and 314 K for La 0.5 Ca 0.45 K 0.05 MnO 3 (LCKM), Nd 0.5 Sr 0.45 K 0.05 MnO 3 (NSKM), and Pr 0.5 Sr 0.45 K 0.05 MnO 3 (PSKM), respectively. From the measured magnetization data as a function of magnetic applied field, we have deduced the associated magnetic entropy change, which reaches a maximum S Max M value of 1.5 1.57 and 1.6 J/kg K for LCKM, PSKM and NSKM respectively under a magnetic applied field of 4 T.