Giant magnetic entropy change in manganese perovskite La0.67Sr0.16Ca0.17MnO3 near room temperature

Abstract

Structural, magnetic and magnetocaloric properties of La0.67Sr0.16Ca0.17MnO3 perovskite have been studied. A solid state reaction method was used in the preparation phase. X-ray diffraction analysis using Rietveld refinement revealed that this sample crystallizes in the distorted rhombohedral system with R3‾c space group. The variation of magnetization (M) vs. temperature (T), under an applied magnetic field of 0.05T, revealed a transition from a ferromagnetic (FM) to paramagnetic (PM) phase at around Curie temperature (TC=336K). Using Arrott plots, it was found that the transition is of a second-order. Isothermal measurements of magnetization allow us, through thermodynamic Maxwell relations, to determine the magnetic entropy change (ΔSM). A large ΔSM deduced from isothermal magnetization curves, has been observed in our sample with a peak centered around its respective TC. The maximum of the magnetic entropy change ΔSMmax in a magnetic field change of 5T is found to be 5.51Jkg−1K−1 at 335K. In addition, the compound showed a large relative cooling power (RCP) value of about 234J/kg while the maximum refrigerant capacity of 174J/kg was attained at the applied field of 5T. As a result, the studied sample can be considered as a potential material for magnetic refrigeration.