DFT analysis of physical properties of quaternary MAX phase nitrides: (Fe0.5M0.5)2SiN (M = Cr & Mn)

MAX phases exhibiting magnetic properties are useful for optoelectronic devices and materials for smart coating. Here, we have investigated the elastic, electronic, magnetic, and thermodynamic properties of newly discovered ordered quaternary MAX phases (Fe0.5M0.5)2SiN (M = Cr & Mn) by using the ab-initio calculation. The Mn- and Cr-substituted Fe2SiN compounds are energetically favorable in the ferromagnetic and antiferromagnetic configurations, respectively. The magnetic properties are predicted using general gradient approximation (GGA) and along with the incorporation of the Hubbard U parameter (GGA + U). The substituted Mn- and Cr-atoms contributed the most to the total magnetic moment of these phases. Formation enthalpy and independent elastic constants confirm their thermodynamical and mechanical stabilities and their mechanical properties are anisotropic in all crystallographic planes. Electronically these phases exhibit metallicity due to the finite number of states at the Fermi level (EF). While evaluating their thermodynamic properties such as lattice parameters, heat capacity at constant volume, and Debye temperature, the (Fe0.5M0.5)2SiN phases turned out to be suitable for high-temperature applications, especially as thermal barrier coatings.

Automated summary

This study investigates the properties of newly discovered ordered quaternary MAX phases (Fe0.5M0.5)2SiN (M = Cr & Mn) using ab-initio calculations. It is found that the Mn- and Cr-substituted compounds are energetically favorable in different magnetic configurations. These phases exhibit metallicity and suitable thermodynamic properties for high-temperature applications.