ANNUAL REPORT - MTA SzFKI

thickness can be elucidated by decomposing the full magnetoresistance curves into FM
and SPM contributions. The decomposition analysis revealed that a minimum observed in
the total magnetoresistance is caused by an interplay between the monotonously
decreasing SPM contribution and the monotonously increasing FM contribution (Fig. 3).
Both components achieved a saturation value at d Cu > 3.2 nm. The variation of the FM and
SPM contributions can be successfully explained by the island model of the SPM regions.
While the SPM cluster size is independent of d Cu , the peak position of the MR curves is
higher when the magnetoresistance components achieved their saturation value. This is
consistent with the assumption that the saturation is related to the more complete
separation of the magnetic layers as d Cu increases. A comparison of the multilayer series
deposited onto Ti and Si/Ta/Cu substrates revealed that the lower surface roughness of the
latter substrate leads to a reduced SPM contribution and, hence, to a higher
magnetoresistance sensitivity close to zero field. The reduced SPM contribution of
samples obtained with smooth Si/Ta/Cu substrates is a consequence of the structural
improvement of the multilayers.
⏐MR⏐ / %
10 Fig. 2(a)
9
8
7
6
5
4
3
2
TMR, total
LMR, total
TMR, FM
LMR, FM
TMR, SPM
LMR, SPM
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
d(Cu) / nm
Fig. 3 Evolution of the total (saturation) magnetoresistance and the FM and SPM contributions with Cu
layer thickness for a multilayer series electrodeposited on Ti. The magnetic layer thickness was 2.0 nm.
Lines are intended only as a guide for the eye.
E-Mail:
Imre Bakonyi bakonyi@szfki.hu
Péter Bánki banki@szfki.hu
Mónika Bokor mbokor@szfki.hu
György Lasanda lasi@szfki.hu
László Péter lpeter@szfki.hu
Kálmán Tompa tompa@szfki.hu
Enikő Tóth-Kádár tke@szfki.hu
Grants and international cooperations
OTKA K 060 821
Investigation of deposits and nanostructures prepared by controlled
precisional electrodeposition (L. Péter, 2006-2008)
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