Spin-wave-assisted thermal reversal of epitaxial perpendicular magnetic nanodots.
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.
Rohart
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S
Laboratoire de Physique des Solides, CNRS, Université Paris Sud, UMR 8502, Bâtiment 510, F-91405 Orsay Cedex, France. rohart@lps.u-psud.fr
Campiglio
P
P
Repain
V
V
Nahas
Y
Y
Chacon
C
C
Girard
Y
Y
Lagoute
J
J
Thiaville
A
A
Rousset
S
S