Density functional theory simulation study of Fe solutes in hcp zirconium: Magnetic and electronic properties

Fe is added to improve corrosion resistance of most commercial Zr alloys. This work aims to study Fe solute stability in different interstitial and substitutional sites in hcp α-Zr lattice and Fe solute ferromagnetic properties within these sites using density functional theory (DFT). A relationship between the electronic and magnetic properties of these Fe solutes and their Zr host atom neighbours was found. The stability of the sites, ranked from most to least stable, is as follows: octahedral, substitutional, basal crowdion, basal octahedral, tetrahedral, and basal tetrahedral. An additional off-site substitutional position was examined to evaluate the influence of Fe solute position on the magnetic properties in Zr. The correlation between the stability of interstitial sites and the amount of charge taken from the surrounding Zr atoms was found using Bader charge analysis. From the perspective of magnetic properties, for all tested sites, only the high symmetry Fe substitution remains magnetised in the Zr lattice. Comparison between the local density of states of the Fe defects and their Zr neighbours suggests the interaction between the d-orbitals of Zr and Fe atoms suppresses the local magnetic moment on Fe interstitials.