AuCo nanoparticles: ordering, magnetisation, and morphology trends predicted by DFT

Area of Science:

• Nanotechnology
• Materials Science
• Condensed Matter Physics

Background:

• Nanoparticles with novel morphologies are crucial for advanced applications leveraging nanoscale magnetism.
• Gold-cobalt (AuCo) nanoalloys offer potential advantages like strong magnetic anisotropy due to combining magnetic cobalt with less reactive gold.

Purpose of the Study:

• To systematically investigate the influence of size and morphology on the energetic and magnetic properties of AuCo nanoparticles.
• To explore the potential of AuCo nanoalloys for tailored magnetic applications.

Main Methods:

• Utilized density functional theory (DFT) calculations to analyze AuCo nanoparticles up to 2.5 nm in diameter.
• Evaluated energetic ordering, total magnetic moments, and magnetic anisotropy.
• Analyzed atom-resolved charges and orbital moments to understand structure-magnetism relationships.

Main Results:

• Identified core-shell icosahedron as the most stable morphology, slightly preferred over the decahedron.
• Observed significantly enhanced magnetic properties (total magnetic moments and magnetic anisotropy) in L1₀ ordered AuCo structures compared to monometallic cobalt nanoparticles.
• Established a clear correlation between AuCo nanoparticle morphology and their magnetic behavior through electronic structure analysis.

Conclusions:

• The study provides a comprehensive understanding of size- and morphology-dependent properties of AuCo nanoparticles.
• Ordered L1₀ structures in AuCo nanoalloys exhibit superior magnetic characteristics, making them promising for advanced applications.
• Findings are expected to guide the rational design of magnetic AuCo nanoalloys for specific technological needs.