Vortex trapping and expulsion in thin-film YBa(2)Cu(3)O(7-delta) strips
Artikel i vetenskaplig tidskrift, 2008

A scanning superconducting quantum interference device microscope was used to image vortex trapping as a function of the magnetic induction during cooling in thin-film YBa(2)Cu(3)O(7-delta) (YBCO) strips for strip widths W from 2 to 50 mu m. We found that vortices were excluded from the strips when the induction B(a) was below a critical induction B(c). We present a simple model for the vortex exclusion process which takes into account the vortex-antivortex pair production energy as well as the vortex Meissner and self-energies. This model predicts that the real density n of trapped vortices is given by n=(B(a)-B(K))/Phi(0) with B(K)=1.65 Phi(0)/W(2) and Phi(0)=h/2e the superconducting flux quantum. This prediction is in good agreement with our experiments on YBCO, as well as with previous experiments on thin-film strips of niobium. We also report on the positions of the trapped vortices. We found that at low densities the vortices were trapped in a single row near the centers of the strips, with the relative intervortex spacing distribution width decreasing as the vortex density increased, a sign of longitudinal ordering. The critical induction for two rows forming in the 35 mu m wide strip was (2.89+1.91-0.93)B(c), consistent with a numerical prediction.

1/f noise

quantum interference devices


ii superconducting strips


K. H. Kuit

Kirteley; John Robert

Chalmers, Mikroteknologi och nanovetenskap (MC2)

W. van der Veur

C. G. Molenaar

F. J. G. Roesthuis

A. G. P. Troeman

J. R. Clem

H. Hilgenkamp

H. Rogalla

J. Flokstra

Physical Review B - Condensed Matter and Materials Physics

1098-0121 (ISSN)

Vol. 77 134504 (art.no.)-


Den kondenserade materiens fysik