New complex magnetic materials for an application in Ericsson refrigerator

In this paper, a new complex magnetic materials La0.70Ca0.15Sr0.15Mn1-xFexO3 (x = 0.000, 0.025, 0.050, 0.075 and 0.100), suitable for the Ericsson cycle, has been investigated. For these materials, the effect of Fe doping can be attributed to a combination of doping disorder, Fe-Mn super exchange interactions and a site-percolation mechanism, which suppress the metallic conduction and ferromagnetism. We have found that these compounds crystallize in the rhombohedral structure with the R (3) over barc space group. We have also verified that the substitution of the manganese with iron leads to an important decrease of the Curie temperature T-C from 335 to 225 K for 0%-10% of Fe. The magnetocaloric study exposes a quite large value of the magnetic entropy change, which decreases when increasing Fe concentration. For an applied magnetic field of 2 T, the Relative Cooling Power (RCP) values are found to vary between 80 and 125 J/kg. As a result, the studied compounds could be considered as potential material for magnetic Ericsson refrigeration by using complex magnetocaloric compounds. (C) 2009 Elsevier Ltd. All rights reserved.