A comparative study of the structural, electronic, magnetic properties and magnetocaloric effect of perovskite LaRO3 (R = Mn, Cr and Fe)

We have investigated the structural, electronic, magnetic properties and magnetocaloric effect of three lanthanum transition-metal oxides, LaMnO3, LaCrO3 and LaFeO3, by a first-principles method based on density functional theory and Monte Carlo simulations. The generalized gradient approximation (GGA) potentials with the U correction (GGA + U) were used for the first-principles calculations. The Monte Carlo study was used to investigate the thermal magnetizations and dM/dT of LaMnO3, LaCrO3 and LaFeO3. The magnetic entropy change and relative cooling power were deduced. Bulk LaCrO3, LaMnO3 and LaFeO3 perovskites exhibit intrinsic weak ferromagnetism at room temperature, which may arise from the tilting of CrO6 octahedra, resulting in a non-zero net magnetic moment, as confirmed from the magnetization calculations. A broad magnetically induced entropy change is observed with maxima at 137, 350 and 785 K, close to room temperature in the LaMnO3 and LaFeO3 systems. (C) 2020 Elsevier Ltd. All rights reserved.