TITLE

Ferromagnetic 0� p Josephson junctions

AUTHOR(S)

Weides, M.; Kohlstedt, H.; Waser, R.; Kemmler, M.; Pfeiffer, J.; Koelle, D.; Kleiner, R.; Goldobin, E.

PUB. DATE

November 2007

SOURCE

Applied Physics A: Materials Science & Processing;Nov2007, Vol. 89 Issue 3, p613

SOURCE TYPE

Academic Journal

DOC. TYPE

Article

ABSTRACT

We present a study on low-Tc superconductor-insulator-ferromagnet-superconductor (SIFS) Josephson junctions. SIFS junctions have gained considerable interest in recent years because they show a number of interesting properties for future classical and quantum computing devices. We optimized the fabrication process of these junctions to achieve a homogeneous current transport, ending up with high-quality samples. Depending on the thickness of the ferromagnetic layer and on temperature, the SIFS junctions are in the ground state with a phase drop of either 0 or p. By using a ferromagnetic layer with variable step-like thickness along the junction, we obtained a so-called 0�p Josephson junction, in which 0 and p ground states compete with each other. At a certain temperature the 0 and p parts of the junction are perfectly symmetric, i.e. the absolute critical current densities are equal. In this case the degenerate ground state corresponds to a vortex of supercurrent circulating clock- or counterclockwise and creating a magnetic flux which carries a fraction of the magnetic flux quantum F0.

ACCESSION #

26691183

Tags: FERROMAGNETIC materials;  FERROMAGNETISM;  FERROMAGNETIC resonance;  MAGNETIC induction;  MAGNETIC flux;  MAGNETIC fields

 

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