Structural, magnetic and magnetocaloric properties of La0.5Sm0.2Sr0.3Mn1-xFexO3 compounds with (0 ≤ x ≤ 0.15)

We have investigated the effect of the substitution of the Mn ions by Fe ions on the structural, magnetic and magnetocaloric behaviors of La0.5Sm0.2Sr0.3Mn1-xFexO3 (0 ≤ x ≤ 0.15) perovskites. The nanocrystalline powders have been synthesized by self-combustion process. Rietveld refinement of fitted and observed X-ray diffractions patterns shows the formation of single-phase compositions with an orthorhombic crystal system (Pnma space group). The variation of magnetization (M) vs. temperature (T) under the field-cooled (FC) and zero-field-cooled (ZFC) modes reveals a ferromagnetic-paramagnetic transition at the Curie temperature (TC). The (TC) decreases linearly with increasing x and changes from 278 K for x = 0 to 94 K for x = 0.15. Arrott plot analyses and a universal curve method were applied for studying the order of the magnetic transition in this system, found to be of second order. Besides, the magnetic entropy change and the related Relative Cooling Power (RCP) values, sensitive to Fe doping, were estimated. In the vicinity of TC, |-ΔSM| reached a maximum value of 3.06 J kg−1 K−1, 2.93 J kg−1 K−1, 2.22 J kg−1 K−1 and 0.77 J kg−1 K−1, whereas the RCP was found to be 268 J Kg−1, 280 J Kg−1, 285 J Kg−1 and 226 J Kg−1 for x = 0.00, 0.05, 0.10 and 0.15, respectively in a magnetic applied field of 5 T. Through these results, La0.5Sm0.2Sr0.3Mn1-xFexO3 materials are strongly suggested for use as active refrigerants for magnetic refrigeration technology near room temperature.