Evidence of L10 chemical order in CoPt nanoclusters: Direct observation and magnetic signature

TitleEvidence of L10 chemical order in CoPt nanoclusters: Direct observation and magnetic signature
Publication TypeJournal Article
Year of Publication2008
AuthorsTournus, F., A. Tamion, N. Blanc, A. Hannour, L. Bardotti, B. Plével, P. Ohresser, E. Bonet, T. Epicier, and éronique. Dupuis
JournalPhysical Review B
Volume77
Issue14
Date Published4/2008
ISSN1098-0121
Abstract

We report the synthesis and characterization of well-defined CoPt clusters with a mean diameter of 3 nm, produced in ultrahigh vacuum conditions following a physical route. Samples made of diluted layers of CoPt clusters embedded in amorphous carbon have been studied by transmission electron microscopy. High-resolution observations have revealed the appearance of L10 chemical order upon annealing, even for clusters with a 2 nm diameter, without cluster coalescence. The magnetic properties of both chemically disordered and ordered CoPt clusters embedded in amorphous carbon have then been measured by x-ray magnetic circular dichroism and superconducting quantum interference device magnetometry. Despite a striking change of the Co magnetic moment, the magnetic anisotropy of chemically ordered nanoparticles increases, with respect to the chemically disordered A1 phase, in much lower proportions than what is observed for the bulk.

DOI10.1103/PhysRevB.77.144411
Short TitlePhys. Rev. B
Undefined