The study of structural, electronic, magnetic and magnetocaloric properties of antiperovskite carbides M3AlC (M=Mn and Fe): DFT combined with Monte Carlo simulation

This work aims to investigate the structural stability, magnetic and electronic properties of M 3 AlC antiperovskites using density functional theory (DFT) and Monte Carlo simulation. The obtained ground state results reveal that the antiperovskites M 3 AlC are stable in the ferromagnetic (FM) state with a metallic character. The calculated total magnetic moments are 5.21[Formula: see text] and 3.34[Formula: see text] for Mn 3 AlC and Fe 3 AlC, respectively, with the total moments mainly from the M atom. The ferromagnetic behavior is confirmed by computing the density of state at Fermi level and verified the Stoner criterion. The magnetic and magnetocaloric behavior of M 3 AlC is investigated using Monte Carlo simulation and the obtained results demonstrate that the transition from ferromagnetic to paramagnetic state occurs at [Formula: see text][Formula: see text]K and [Formula: see text][Formula: see text]K for Mn 3 AlC and Fe 3 AlC, respectively. These values of [Formula: see text] are in good agreement with the experimental results. The magnetocaloric effect and critical behavior are studied and the obtained values of magnetic entropy change [Formula: see text] at 4.5[Formula: see text]T is about 4.242[Formula: see text]J/kg.K and 3.666[Formula: see text]J/kg.K and the relative cooling power (RCP) are 342.434[Formula: see text]J/kg.K and 325.26[Formula: see text]J/kg.K for Mn 3 AlC and Fe 3 AlC at 4.5T, indicating that these compounds are more appropriate for magnetic refrigeration. Finally, the critical exponents ([Formula: see text],[Formula: see text],[Formula: see text]) are calculated and the obtained values are close to the values of mean-field model.