Large room temperature relative cooling power in La0.5Pr0.2Ca0.1Sr0.2MnO3

The La0.5Pr0.2Ca0.1Sr0.2MnO3 compound has been investigated as a potential candidate for room temperature magnetocaloric refrigeration. The Rietveld refinement of X-ray powder diffraction patterns confirms that the compound crystalizes in an orthorhombic phase with the Pnma space group. Rutherford backscattering spectrometry and time-of-flight elastic recoil detection analysis, verified the desired ratio of the elements in the compound. Using X-ray photoelectron spectroscopy two oxidation states of manganese (Mn), Mn4+ and Mn3+ were identified in the compound with relative amounts of 32% and 68%, respectively. The observed spin orbit splitting of the Mn-2p(3/2) and Mn-2p(1/2) levels was obtained as 11.7 eV. A ferromagnetic to paramagnetic transition was observed around 296 K, which makes the material interesting for magnetic cooling near room temperature. In addition, the absence of magnetic hysteresis provides another argument in favor of the studied compound. The isothermal entropy change (-Delta S-M) and the relative cooling power (RCP) for a magnetic field change of 5 T were found to be 4 J/kg K and 372 J/kg, respectively. From the comparison of the values of -Delta DSM and RCP with those obtained for the archetypal magnetocaloric material gadolinium, it is argued that our material can be considered as a potential candidate in cooling systems based on magnetic refrigeration. (C) 2020 Elsevier B.V. All rights reserved.