TY - JOUR
T1 - Model predictions and experimental characterization of Co-Pt alloy clusters
AU - Moskovkin, P.
AU - Pisov, S.
AU - Hou, M.
AU - Raufast, C.
AU - Tournus, F.
AU - Favre, L.
AU - Dupuis, V.
PY - 2007/7
Y1 - 2007/7
N2 - Model and real cobalt-platinum alloy clusters are compared in terms of structure, composition and segregation. Canonical and semi grand canonical Metropolis Monte Carlo simulations are performed to model these clusters, using embedded atom (EAM) and modified embedded atom (MEAM) potentials. All of them correctly predict the bulk L12 Co3Pt and CoPt3 structures as well as the L10 CoPt phase. However, the lattice parameters, phase stability and the L10-fcc order-disorder transition temperature are at variance. Segregation predictions with EAM and MEAM potentials are contradictory. Experimentally, mixed clusters with various compositions were deposited by Low Energy Cluster Beam on amorphous carbon at room temperature. Their size distribution, crystalline structure and composition were examined by Transmission Electron Microscopy (TEM). Clusters with the same size distributions were modelled. Both experiment and modelling show their crystallographic parameters to continuously correspond to the fcc CoPt chemically disordered phase. Diffraction measurements indicate surface segregation of the specie in excess, in agreement with EAM predictions for the Co-rich phase. The consequences on magnetic properties are discussed.
AB - Model and real cobalt-platinum alloy clusters are compared in terms of structure, composition and segregation. Canonical and semi grand canonical Metropolis Monte Carlo simulations are performed to model these clusters, using embedded atom (EAM) and modified embedded atom (MEAM) potentials. All of them correctly predict the bulk L12 Co3Pt and CoPt3 structures as well as the L10 CoPt phase. However, the lattice parameters, phase stability and the L10-fcc order-disorder transition temperature are at variance. Segregation predictions with EAM and MEAM potentials are contradictory. Experimentally, mixed clusters with various compositions were deposited by Low Energy Cluster Beam on amorphous carbon at room temperature. Their size distribution, crystalline structure and composition were examined by Transmission Electron Microscopy (TEM). Clusters with the same size distributions were modelled. Both experiment and modelling show their crystallographic parameters to continuously correspond to the fcc CoPt chemically disordered phase. Diffraction measurements indicate surface segregation of the specie in excess, in agreement with EAM predictions for the Co-rich phase. The consequences on magnetic properties are discussed.
UR - http://www.scopus.com/inward/record.url?scp=34249675695&partnerID=8YFLogxK
U2 - 10.1140/epjd/e2007-00066-0
DO - 10.1140/epjd/e2007-00066-0
M3 - Article
AN - SCOPUS:34249675695
SN - 1434-6060
VL - 43
SP - 27
EP - 32
JO - European physical journal. D: Atomic, molecular and optical physics
JF - European physical journal. D: Atomic, molecular and optical physics
IS - 1-3
ER -