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TT: Tiefe Temperaturen

TT 8: Supraleitung: Dünne Schichten, Josephsonkontakte, SQUIDs

TT 8.4: Vortrag

Dienstag, 25. März 2003, 10:30–10:45, HSZ304

Transport characteristics of Nb/Al₂O₃/Co/Al₂O₃/Nb devices — •Simon Stein¹, Martin Weides¹, Timo Nachtrab², Edward Goldobin², Dieter Kölle², Hermann Kohlstedt¹, and Reinhold Kleiner² — ¹Institut für Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich — ²Physikalisches Institut-Experimentalphysik II, Universität Tübingen, D-72076 Tübingen

We study Josephson coupling in hybrid superconductor-ferromagnet tunnelling devices. Combining processes for Co/AlO_x/Co magnetic tunnelling junctions and Nb/Al/AlO_x/Nb Josephson junctions we fabricated hybrid superconductor-ferromagnet planar junctions. The lay-out of these multilayers is Nb120/Al5+Oxidation/Co3/Al1.3+Oxidation/Nb30 (layer thicknesses in nm). The process parameters are derived from Josephson junctions with critical currents of about 1 kA/cm². The junctions are lithographically structured down to junction areas of 1 µm².

First transport measurements of the junctions show Andreev-reflection-like behaviour. We will discuss the observance of the π-phase, and advanced designs for combined 0-π-junctions (cf. 1).

(1) E. Goldobin et al., PRB 66, 100508 (2002)