Surface structures of the magnetostrictive D03-Fe3Ga(001)

TL;DR

This study combines first-principles calculations and experiments to identify and analyze stable surface reconstructions of the magnetostrictive Fe3Ga alloy, revealing atomic exchange-induced stripe patterns and their implications for magnetic applications.

Contribution

It provides the first detailed characterization of Fe3Ga surface reconstructions, linking atomic exchanges to stripe domain patterns and surface stability.

Findings

Identified stable 1x1 and 3x1 surface reconstructions.

Good agreement between theoretical STM simulations and experimental images.

Strain enhances the stability of the 3x1 reconstruction.

Abstract

First-principles total energy calculations and experimental measurements were performed to study the surface reconstructions of the magnetostrictive Fe3Ga alloy. The magnetostrictive behavior was evaluated in the bulk by compressing and stretching its lattice parameter. Results demonstrate two thermodynamically stable surfaces, the 1x1 and 3x1 reconstructions. The 1x1 is an ideally FeGa terminated surface whereas the 3x1 is also FeGa terminated but it has a first-layer Fe atom substituted by a Ga atom every three unit-cells, forming stripe-like domain patterns. Tersoff-Hamann scanning tunneling microscopy simulations were obtained and compared with experimental results. We found good agreement between theory and experiment, in which the distance between rows is ~1.23 nm. The substrate-induced strain increases the stability of the 3x1 reconstruction. Here we have demonstrated that Ga/Fe atomic exchanges lead to the stripe-like domain patterns. Clarification of the atomic reconstructions present on the magnetostrictive Fe3Ga alloys is an important step towards the understanding of its surfaces and poses this system as a potential candidate to be used as part of perpendicular magnetic tunnel junctions due to the existing perpendicular magnetic anisotropy effect when grown on different substrates.