Surface diffraction on magnetic nanostructures in thin films using grazing incidence SANS. M....
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Surface diffraction on magnetic nanostructures in thin films using grazing incidence SANS. M. Pannetier (a) , F. Ott (b) , C. Fermon (b) , Y. Samson (c) (a) DRECAM/SPEC, CEA Saclay, 91191 Gif sur Yvette FRANCE (b) Lab. Léon Brillouin CEA/CNRS, 91191 Gif sur Yvette FRANCE (c) CEA Grenoble DRFMC/SP2M, 17 rue des Martyrs 38054 Grenoble France
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Transcript of Surface diffraction on magnetic nanostructures in thin films using grazing incidence SANS. M....
Surface diffraction on magnetic nanostructures in thin films
using grazing incidence SANS.
M. Pannetier(a), F. Ott(b), C. Fermon(b), Y. Samson(c)
(a) DRECAM/SPEC, CEA Saclay, 91191 Gif sur Yvette FRANCE(b) Lab. Léon Brillouin CEA/CNRS, 91191 Gif sur Yvette FRANCE
(c) CEA Grenoble DRFMC/SP2M, 17 rue des Martyrs 38054 Grenoble France
Outline
Principle of the experiment
Scattering on a FePd system
Data simulations
Other prospective systems
Principle of the experiment
Under total reflection angle (c) an evanescent wave is travelling parallel to the surface
penetration depth 10-50 nm
i < c
ki kf
Scattering geometry
z
x y
neutrons
Incidence plane10-4 < Qy < 10-2 nm-1
600 nm < < 60 µm
incidence plane10-2 < Qy < 3 nm-1
10-1 nm < < 100 nm
Experimental set-up
Spectrometer PAPOL at the LLB Saclay
sampleslit 1H
Specular reflected beam
Incidence angle on the sample i
slit 2H
diffracted beam
polariser
Detector
Y
X
Z
FePd layers
Fe0.5Pd0.5 alloy layers “self-organise” in magnetic stripes
Domain sizes : 60 nmWall thickness : 6 nm
Magnetic domains
Field B = Hd + M
Simulation OOMMF
DRFMC CEA Grenoble
Magnetic sensitivity
Top view
ki
kf
qy
The domains magnetisation contribute to the scatteringNeel caps do not contributeBloch wall do contribute
Néel cap
Mup
Mdo
M and B components in the layerM B
X
Y
Z
-60
-40
-20
0
20
40
60
0
position
Fie
ld
Field Y
Field Z
-100
-50
0
50
100
0
position
Fie
ld
MagY
Mag Z
GID scattering on the PSD
c = 0.7°
Beam stop
diffraction
Specular line
Refracted signalQy
Qz
Calcul plus complet (facteur de forme inclus)
Sin(PhiF) vs Sin(Theta out) ; Theta In = 0.2° (stupide) Gauche ligne sur substrat; droite “vraie situation” (sauf épaisseur) Les échelles de couleurs ne corespondne tpas du tout au meme
intensités!!!
Problem of the stray fields
The stray fields are not negligible – They create a rather large magnetic potential
outside the layer
GID
2D grating (top view)
TF
Rods
2/d
d
Ewald sphere
ki
kf
ki
Other example : Co clusters in Al2O3
Co/Al2O3D.Babonneau et al, APL 76 (2000)
2/ 5.4nmGISANS
Correlationfonction
Formfactor
