Seminars Archive
Salia Cherifi
Abstract
Tuesday, September 19, 2000, 14:30
Seminar Room, ground floor, Building "T"
Sincrotrone Trieste, Basovizza
Step-induced in-plane magnetic anisotropy in Fe
0.65
Ni
0.35
ultrathin
films grown on Cu(111) vicinal surfaces
Salia Cherifi
(IPCMS-GSI, Srasbourg France)
ABSTRACT
We focus in this work on the step-induced in-plane Magnetic Anisotropy
(MA) of Fe0.65Ni0.35 fcc alloy films to understand the role of lattice
symmetry breaking and the strain effects in this MA.
In order to correlate the step-induced MA to the structural parameters,
we characterised these systems using AES, LEED, STM, and Surface-EXAFS
facilities. By STM we show that FeNi co-evaporation on vicinal Cu(111)
single crystals leads to 1-dimensional (1D) wires below 2 ML coverage,
related to the step decoration growth mode and at 2 ML, 2D coalescence
starts. Polarisation dependent S-EXAFS results reveal an in-plane anisotropy
of the lattice parameter appearing after this 2D coalescence. Angle-dependent
XMCD measurements at the Fe L2,3 edges were performed at ESRF (ID12B) in
order to extract the in-plane and out-of-plane magnetic moment anisotropies.
The changes of the magnetic moment values (ML, MS) are determined by applying
the sum rules to the XMCD data for different thicknesses (1D, before and
after the 2D coalescence).
The results show that the orbital moment ML depends strongly on thicknesses
and as well on the azimuth angles. The most important effects are observed
for 1D wires and strained films. We explain these results in the light
of the shape and structural in-plane anisotropies of the nanostructures.
