Magnetic, magnetocaloric and transport properties in AlCMn3 antiperovskite compound

In this work, the aim was to conduct a numerical study of the structural, electronic, magnetic, magnetocaloric, and transport-related properties of the antiperovskite compound AlCMn3, by using several theoretical methods such as: ab initio calculations, Monte Carlo simulations, and mean field theory. This material exhibits a second-order ferromagnetic-paramagnetic phase transition around TC = 287 K. The crystal field and the parameters of the exchange coupling interactions have been investigated using ab initio methods. A previous theoretical study based on the magnetoelastic and magnetoelectronic couplings was investigated in order to calculate the magnetocaloric effect (MCE) of AlCMn3, but the results that were obtained using this method (namely a magnetic entropy change of -ΔSm = 35 J/Kg. K) did not match the experimental value of -ΔSm = 3.28 J/Kg.K under the same applied magnetic field of 4.5T, which is why we resorted to using the Monte Carlo simulation. This new approach improved MCE-related results as they ended up matching the experimental data, contrary to the magnetoelastic and magnetoelectronic couplings method. This suggests that AlCMn3 may be considered as a potentially viable material for magnetic refrigeration at near-room temperature due to: (i) the large full width at half peak of its −ΔSm (T) curve, (ii) the absence of any hysteresis loss, (iii) its near-room temperature working conditions and (iv) the low cost and innocuous nature of its raw materials.