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

Abstract

This work aims to investigate the structural stability, magnetic and electronic properties of M3AlC antiperovskites using density functional theory (DFT) and Monte Carlo simulation. The obtained ground state results reveal that the antiperovskites M3AlC 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 Mn3AlC and Fe3AlC, 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 M3AlC 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 Mn3AlC and Fe3AlC, 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 Mn3AlC and Fe3AlC 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.