title: Theoretical and experimental characterization of structures of MnAu nanoclusters in the size range of 1-3 nm.
abstract: Relative stabilities of MnAu magic-number nanoclusters with 55, 147, 309, and 561 atoms and highly symmetric morphologies (cuboctahedron, icosahedron, onion-like, and core-shell, respectively) are investigated based on density functional theory methods. Through an extensive search, spin arrangements on Mn atoms that give rise to lowest-energy clusters are predicted. The antiferromagnetic spin configurations are found to be the most favorable for all morphologies investigated. The energy rankings among MnAu nanoclusters with the same size and Mn/Au ratio but different morphologies are also determined. The L1(0) structure is found to be increasingly favorable as the size increases from 1.0 to 2.9 nm, consistent with experimental measurements of MnAu nanoparticles in the size range of 1.8-4.6 nm. The decahedron L1(0) morphology is found to be energetically more preferred when the Mn/Au ratio is close to 1:2, whereas the cuboctahedron L1(0) morphology is more preferred when the Mn/Au ratio is close to 1:1. The calculated lattice constants are in excellent agreement with high-resolution TEM measurements for MnAu nanoparticles of similar size. Magnetic states of MnAu nanoclusters are predicted to be stable at room temperature based on estimated Curie or Neél temperature.
authors: Department of Chemistry and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, United States.
authors: Rulong
authors: R
authors: Zhou
authors: Xiaohui
authors: X
authors: Wei
authors: Kai
authors: K
authors: He
authors: Jeffrey E
authors: JE
authors: Shield
authors: David J
authors: DJ
authors: Sellmyer
authors: Xiao Cheng
authors: XC
authors: Zeng
mesh_terms: D003198:Computer Simulation; D006046:Gold / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D008422:Materials Testing; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D008345:Manganese; D006046:Gold