title: Spin-wave-assisted thermal reversal of epitaxial perpendicular magnetic nanodots.
abstract: The magnetic susceptibility of self-organized two-dimensional Co nanodots on Au(111) has been measured as a function of their size in the 2-7 nm diameter range. We show that the activation energy for the thermal reversal displays a power law behavior with the dot volume. Atomic scale simulations based on the Heisenberg Hamiltonian show that this behavior is due to a deviation from the macrospin model for dot size as small as 3 nm in diameter. This discrepancy is attributed to finite temperature effects through the thermal excitation of spin-wave modes inside the particles.
authors.affiliation: Laboratoire de Physique des Solides, CNRS, Université Paris Sud, UMR 8502, Bâtiment 510, F-91405 Orsay Cedex, France. rohart@lps.u-psud.fr
authors.forename: S
authors.initials: S
authors.lastname: Rohart
authors.forename: P
authors.initials: P
authors.lastname: Campiglio
authors.forename: V
authors.initials: V
authors.lastname: Repain
authors.forename: Y
authors.initials: Y
authors.lastname: Nahas
authors.forename: C
authors.initials: C
authors.lastname: Chacon
authors.forename: Y
authors.initials: Y
authors.lastname: Girard
authors.forename: J
authors.initials: J
authors.lastname: Lagoute
authors.forename: A
authors.initials: A
authors.lastname: Thiaville
authors.forename: S
authors.initials: S
authors.lastname: Rousset