Systematic investigation of physical properties of Mg₃XO₄ (X = Cr, Mn, Fe, Co, Ni); a computational approach

Abstract Material development is primarily dependent on their design and theoretical exploration. Density functional theory is a great tool to achieve this goal. Here, Mg 3 XO 4 (X = Cr, Mn, Fe, Co, Ni) are considered in order to reveal their full characteristics using density functional theory. Mg 3 XO 4 (X = Cr, Mn, Fe, Co, Ni) are investigated in terms of their structural, elastic, mechanical, thermodynamic, electronic, and dynamic properties. The formation energies for Mg 3 XO 4 (X = Cr, Mn, Fe, Co, Ni) are found to be negative implying synthesisability and dynamic stability of these materials. The evolution of elastic constants of materials demonstrates that all materials satisfy the Born stability criterion, hence Mg 3 XO 4 (X = Cr, Mn, Fe, Co, Ni) are mechanically stable. Several polycrystalline parameters are derived by using elastic constants and evaluated. All materials are found be brittle, hard (Vickers hardness) and magnetic. They exhibit some degree of anisotropy in Young/Shear modulus and Poisson’s ratio. The electronic band structures for Mg 3 CrO 4 , Mg 3 MnO 4 and Mg 3 FeO 4 indicated a semi-metallic nature whereas for Mg 3 CoO 4 and Mg 3 NiO 4 indicated metallic nature because both the majority and minority energy bands cut the Fermi level. The phonon modes are found to be in positive frequencies that confirms dynamical stability. The materials’ free energy, entropy, specific heat capacity, Debye and melting temperatures, minimum thermal conductivity and Grüneisen parameters are also obtained and discussed.