Influence of noble metal dopants (M = Ag, Au, Pd or Pt) on the stable structures of bimetallic Co-M clusters

A Perspective on Modelling Metallic Magnetic Nanoparticles in Biomedicine: From Monometals to Nanoalloys and Ligand-Protected Particles

“…For biomedical applications, the alloying of cobalt with more inert metals such as silver or gold has proved to be a valuable strategy to obtain biocompatibility and reduce oxidation. In accordance with the large differences in atomic radii in favour of inert metals, and weak Ag-Co/Au-Co miscibility predicted below 400 • C across all compositional space [427], theoretical studies have reported structures that favour Ag/Au surface segregation and the formation of core-shell orderings [402,428,429]. Experimental synthesis has confirmed theoretical predictions, and core-shell AuCo mNPs were found to have mostly icosahedral structure, although a novel morphology has been recently described consisting of a Co icosahedron surrounded by fcc Au facets [430][431][432].…”

“…The applicability of single-component mNPs is restricted by limited property-tuning possibilities. To overcome this limitation, mNPs can be modified through the construction of bimetallic architectures consisting of two distinct metals, one or both of which should be magnetic [397][398][399][400][401][402]. Bimetallic (and multimetallic) mNPs, often referred to as magnetic nanoalloys, present properties with a very high degree of tunability owing to the variety of morphologies they can adopt.…”

Understanding the shape effect on the structural, energetic, magnetic, and pressure properties of the 38 atom-Co-Fe-Pd nanoalloys using Gupta and DFT calculations

“…In recent years, the alloying process containing magnetic elements has led to the development of advanced multifunctional materials in nanotechnology [3]. Especially, the nanoalloys consist of magnetic elements such as Fe, Co or Ni, and non-magnetic elements such as Ag, Au, Pd or Pt have gained considerable importance since they display the magnetism from the 3d metals and the catalytic properties of the noble metals [4]. Especially Co-Pd nanoalloys have shown promising performance, and thus, the properties of Co-Pd nanoalloys have been examined in both experimental and theoretical studies.…”

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

“…In accordance with the disproportionate radii and immiscibility predicted below 400 1C across all composition space, 40 theoretical studies reported structures that favour Au surface segregation and the formation of core-shell orderings. [41][42][43] A novel statistical-mechanics approach to determine the free energy cost of forming phase-separated aggregates developed by Ferrando et al has shown that the decrease in cost is nonnegligible for AuCo NPs with diameters up to 10 nm, thus indicating the permanence of an equilibrium miscibility gap at the nanoscale and the nonexistence of a critical size below which phase separation is impossible. 44 The global minimum geometries were corroborated by molecular dynamics studies, where rosette reconstructed icosahedra were found to be the most stable for systems with compact Co cores, whereas nanoparticles with larger Co core sizes adopted the shapes of regular Mackay icosahedra with central high-symmetry cores.…”