Highly ordered single domain Fe2-xCo1+xGa (0 ≤ x ≤ 1) nanoparticles synthesized by a template-less chemical route

Abstract

A comprehensive study has been carried out on chemically synthesized Fe2-xCo1+xGa (0 ≤ x ≤ 1) nanoparticles using both experimental and theoretical tools. Adoption of a template-free preparation route ensured impurity-free and phase-pure Heusler alloy nanoparticles. Depending on the composition, these nanoparticles exhibit highly ordered L21 or X type Heusler alloy structure. These nanoparticles have high saturation magnetization (3.90 – 5.15 µB/f.u.), high Curie temperature (≥ 1100 K) and high effective anisotropy constant (∼ 106 erg/cc) along with low coercive field (≤ 12 Oe) and low remnant magnetization (≤ 0.03 µB/f.u.). Emergence of superparamagnetism in these single (magnetic) domain nanoparticles is another interesting aspect. The electronic density of states of these alloys near Fermi level have also been evaluated as a function of composition using ab initio calculations. These results indicate Fe2-xCo1+xGa nanoparticles to be promising candidates for high density magnetic media and nanomagnetic sensor applications.