The structural, magnetic and above room temperature magnetocaloric properties of La0.5Sr0.5MnO3 compound

We have carried out the structural properties, magnetization measurements and magnetocaloric effects in La0.5Sr0.5MnO3 perovskite prepared by the solid-state reaction formula. Crystallographic analysis was realized by Rietveld refinement of experimental X-ray diffraction data. Results show that this material has tetragonal crystal structure and exhibits a sharp ferromagnetic-paramagnetic (FM-PM) transition at a Curie temperature T-C (352 K). The experimental magnetic entropy change (-Delta S-M) and the relative cooling power (RCP) have been determined. The magnetocaloric data show a moderate low field magnetic entropy change above room temperature. In addition, the RCP values vary from 46.40 to 228.35 J kg(-1) upon variation of the applied magnetic field at 1 and 5T, which is about 56% of the conventional refrigerant Gd material under 5 T. A good agreement is found between the experimental (-Delta S-M) and the one estimated by the Landau theory at the ferromagnetic region. However, the discrepancy at paramagnetic region was assigned to the contribution of itinerant electron to the large magnetic entropy change.