Dresden 2003 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 8: Supraleitung: Dünne Schichten, Josephsonkontakte, SQUIDs

TT 8.7: Vortrag

Dienstag, 25. März 2003, 11:15–11:30, HSZ304

Semifluxon dynamics in long Josephson 0-π-junctions — •Edward Goldobin, Dieter Koelle, and Reinhold Kleiner — Physikalisches Institut - Experimentalphysik II,Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen

We investigate the dynamics of vortices containing half integer flux quanta in long Josephson 0-π-junctions of linear geometry. Such vortices were theoretically predicted and have been already observed in several types of long Josephson 0-π-junctions (tri-crystal grain boundaries, YBCO-Nb zigzag ramps, SFS or SIFS junctions). Semifluxons exist solely due to the Josephson phase π-discontinuities at the points where 0 and π parts join. In many cases semifluxons are just pinned at discontinuities or oscillate around them. But at certain conditions semifluxons can also move by hopping from one discontinuity point to another, provided the distance between discontinuity points is not much larger than the Josephson penetration depth. Such hopping may be controlled by bias current and opens a convenient possibility to control the semifluxon configuration. The hopping may take place even between a real and an imaginary π-discontinuity point situated outside the junction, which results in the formation of half integer zero-field steps.