https://doi.org/10.1140/epjd/e2012-30451-3
Regular Article
Finite size effects on structure and magnetism in mass-selected CoPt nanoparticles*
1
LPMCN, UMR 5586 CNRS/Université de Lyon,
69622
Villeurbanne Cedex,
France
2
ITP, Institut für Theoretische Physik, Universität
Kassel, 34132
Kassel,
Germany
3
European Synchrotron Radiation Facility,
BP 220, 38043
Grenoble Cedex,
France
Received:
19
July
2012
Received in final form:
8
November
2012
Published online:
26
February
2013
Abstract
We have studied size effect on the local structure and magnetism in CoPt clusters embedded in carbon matrix upon annealing in the 2–4 nm diameter range. From Co-K and Pt-L edges extended X-ray absorption fine structure (EXAFS) experiments and simulations, we report the refined quantitative non trivial structure of size-selected 3 nm in diameter CoPt magnetic clusters. In agreement with ab-initio simulation calculations, we evidenced an element-specific dependence of the local atomic relaxations in CoPt clusters leading to a strong distortion in pure Co planes. Since pure Co layers do not match the underlying Pt layer in chemically ordered L10-like clusters, we claim that a perfect crystal can not exist at nanosize. Such result could explain the low magnetic anisotropy energy measured on chemically ordered CoPt nanomagnets assemblies.
ISSPIC 16 – 16th International Symposium on Small Particles and Inorganic Clusters, edited by Kristiaan Temst, Margriet J. Van Bael, Ewald Janssens, H.-G. Boyen and Françoise Remacle.
Present address: Institut Lumière Matière, UMR 5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex, France.
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Present address: Currently at Institut NÉEL, CNRS and Université Joseph Fourier, BP 166, 38042 Grenoble Cedex 9, France.
Present address: Currently at Facultad de Ciencias, Universidad Autónoma del Estado de México, Av. Instituto Literario 100, Col. Centro, Toluca, C.P. 50000, México.
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2013
