Goldobin E, Sterck A, Gaber T, Koelle D, Kleiner R
Physikalisches Institut, Experimentalphysik II, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tuebingen, Germany.
Phys Rev Lett. 2004 Feb 6;92(5):057005. doi: 10.1103/PhysRevLett.92.057005.
We propose, implement, and test experimentally long Josephson 0-pi junctions fabricated using conventional Nb-AlOx-Nb technology. We show that by using a pair of current injectors one can create an arbitrary discontinuity of the Josephson phase and, in particular, a pi discontinuity, just as in d-wave/s-wave or in d-wave/d-wave junctions, and study fractional Josephson vortices which spontaneously appear. Moreover, using such junctions, we can investigate the dynamics of the fractional vortices-a domain which is not yet available for natural 0-pi junctions due to their inherently high damping. We observe half-integer zero-field steps which appear on the current-voltage characteristics due to the hopping of semifluxons.
