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Struktur und Dynamik Poster: Mi., 14:00–16:30 M-P149
Improved growth of Fe/V-superlattices due to H-assistance
Gregor Nowak 1 , Arndt Remhof 1 , Andreas Liebig 2 , Moreno Marcellini 2 ,
Kurt Westerholt 1 , Björgvin Hjörvarsson 2 , Hartmut Zabel 1
1 Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, Germany
– 2 Department of Physic, University Uppsala, Regementsvägen 1, 75121 Uppsala,
Sweden
We studied the influence of hydrogen on the growth of sputter deposited V single
layers and on [Fe(2ML)/V(16ML)]×30 superlattices. We show that the high structral
quality achieved previously [1] can be further improved by using hydrogen enriched Argon
(pAr=7 mbar)as process gas during sputter deposition. At each chosen hydrogen
pressure of up to 2×10 −6 mbar we prepared a series of samples at substrate temperatures
between 270 ◦ C and 320 ◦ C. The structural characterization was carried out by
x-ray diffraction at the wiggler beamline W1.1 at the Hamburg synchrotron laboratory
(HASYLAB). Three trends are observed. The mosaicity decreases, the interface quality
increases (Fig. 1), and the transport measurements of 240 ˚A thick V single layers
grown in H-enriched sputter gas reveal a 53 % higher residual resistivity ratio of 14.2
in comparison to V-layers grown without H-enrichment (Fig. 2). The residual resistivity
ratio is a direct measure of the Cooper pairs coherence length which we could
increase due to the H-enrichment by 25 % to 232 ˚A in V. The Cooper pair coherence
length is mainly limited by scattering on structural and chemical defects which could
be reduced in the H-enrich sputter process. We attribute this effects to an increased
surface mobility of the metal atoms in the presence of hydrogen during the sputtering
process [2].
This project was funded by the DFG under contract-Nr. RE 2203-1/1
[1] P. Isberg et al., Vacuum, 48 (1997) 483.
[2] Horch et al., Nature, 398 (1999) 132.
Fig. 1: X-ray radial scans of the Fe/V
superlattices.
Fig. 2: Transport measurements for
26 nm thick V single layers.