Stability of Ir-Fe alloys and nitrides Ir-Fe-N through first principles models

Abstract

The theoretical prediction of compounds' properties is a desired dream by physicists, chemists and materials engineers; here we will establish a model to predict the stability of alloys, using first-principles LAPW calculations (Linearized Augmented Plane Waves) which is a APW modification (Augmented Plane Waves Method of Slater). We propose to calculate the energy of formation and cohesive energy of iridium-iron alloys and iridium-iron nitrides. In this discussion we will find a methodology that can be applied to solids with different atoms, creating a model to calculate the stability of these alloys. In our calculations we found a unit cell volume with a high increase when we changed from alloys to nitrides, thereby strongly influencing the energy of formation and cohesive energy. We also study the pressure in response to changes in the volume and the total energy of the compound, verifying that the same volume of balance was found in the minimum of cohesive energy of compounds at zero pressure. Finally, we discuss the critical pressure between ferromagnetic and non-magnetic phases, which proves to be of the same order of magnitude of some experimental and theoretical results of other systems. © 2012 Elsevier B.V. All rights reserved.