TY  - JOUR
AU  - Faley, M. I.
AU  - Reith, P.
AU  - Stolyarov, V. S.
AU  - Golovchanskiy, I. A.
AU  - Golubov, A. A.
AU  - Hilgenkamp, H.
AU  - Dunin-Borkowski, R. E.
TI  - π-Loops With ds Josephson Junctions
JO  - IEEE transactions on applied superconductivity
VL  - 29
IS  - 5
SN  - 1051-8223
CY  - New York, NY
PB  - IEEE
M1  - FZJ-2019-01195
SP  - 1 - 5
PY  - 2019
AB  - We fabricated Josephson junctions (JJs) between the d-wave superconductor (SC) YBa 2 Cu 3 O 7 -x (YBCO) and the s-wave SC Nb (ds-JJs) on graphoepitaxially buffered MgO substrates, studied ds-JJs at temperatures down to 30 mK and employed these JJs in π-loops. Current-voltage characteristics of ds-JJs oriented along the [100] axis of YBCO exhibited up to a factor of 200 higher critical current densities than ds-JJs oriented along the [110] axis of YBCO. The critical current Ic and the IcRn product of [100]-oriented 3 μm wide ds-JJs are ∼70 μA and ∼200 μV, respectively, at 4.2 K. Rectangular arrays of up to 40 000 π-loops based on such ds-JJs were investigated using a low temperature scanning superconducting quantum interference device (SQUID) microscope. We observed ordering of spontaneously generated half integer magnetic flux quanta in the π-loops correlated with minute spurious background magnetic fields, as well as with configurations and mutual coupling of the π-loops. We manipulated the magnetic states of the π-loops by the local application of magnetic fields using nearby planar coils. This paper paves the way for the use of π-loops in computations that are based on annealing processes.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000457591700001
DO  - DOI:10.1109/TASC.2019.2892078
UR  - https://juser.fz-juelich.de/record/860441
ER  -