Electronic structure and pressure dependence of magnetic properties of Fe/N/Fe multi-layers

The electronic structure and magnetic properties of the Fe/N/Fe multi-layers were obtained by means of self-consistent band structure calculations employing the Linear Muffin-Tin Orbital method (LMTO). Calculations were carried out for several lattice parameters in order to obtain ground-state properties such as equilibrium lattice parameters and the critical pressure of these multi-layers. The analysis of the density of states at equilibrium volume gives a good understanding of the electronic and magnetic properties of these multi-layers, showing remarkable differences from the bulk properties of iron-based nitrides. Ferromagnetic calculations show that the Fe/N/Fe multi-layers, at equilibrium volume, have a ferrimagnetic order of 1.45 lB and –0.22 lB as the magnetic moments at the two non-equivalent iron sites. At nitrogen sites a moment magnetic of –0.16 lB was found, which is opposite to the very small values found in bulk iron nitrides. The magnetic moment and hyperfine field (the Fermi Contact) show a strong dependence with the lattice spacing with a collapse of the magnetic moments at certain critical lattice spacing