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AM: Magnetismus
AM 12: Oberfl
ächenmagnetismus
AM 12.9: Vortrag
Donnerstag, 29. März 2001, 11:30–11:45, S 5.4
Metastable ferromagnetism of Co/Cu(001) below the TC-jump — •P. Poulopoulos, A. Ney, J. Lindner, E. Kosubek, H. Wende, and K. Baberschke — Freie Universität Berlin, Institut für Experimentalphysik, Arnimallee 14, D-14195 Berlin-Dahlem, Germany
Co/Cu(001) ultrathin films is a well-studied system in terms of
magnetism and growth. Recently
it was found that a sudden jump of the Curie temperature TC occurs as
a function of the film
thickness at about 1.8 monolayers (ML) [1] due to the coalescence of the
Co islands upon
completing the second ML. Here we show by soft annealing to 400-500 K that
below 1.8 ML
the films present metastable structural and magnetic behavior. Scanning
tunneling microscopy
is used to monitor the structure. A combination of in situ techniques such
as magneto-optic
Kerr effect, ferromagnetic resonance and SQUID magnetometry reveals an
increase of the
magnetization and TC for the annealed films with respect to the
as-grown ones at
room temperature. This striking behavior is attributed to thermally
assisted island coalescence
and phase separation of Co and Cu.
Gefördert durch DFG, Sfb 290, TP A 02 und BMBF (05SC8 KEA3).
[1] U. Bovensiepen et al., J. Magn. Magn. Mater. 192, L386 (1999)