Analysis of low-field isotropic vortex glass containing vortex groups in YBa2Cu3O(7-x) thin films visualized by scanning SQUID microscopy.
The glass-like vortex distribution in pulsed laser deposited YBa2Cu3O(7-x) thin films is observed by scanning superconducting quantum interference device microscopy and analysed for ordering after cooling in magnetic fields significantly smaller than the Earth's field. Autocorrelation calculations on this distribution show a weak short-range positional order, while Delaunay triangulation shows a near-complete lack of orientational order. The distribution of these vortices is finally characterised as an isotropic vortex glass. Abnormally closely spaced groups of vortices, which are statistically unlikely to occur, are observed above a threshold magnetic field. The origin of these groups is discussed, but will require further investigation.
Institute for Superconducting and Electronic Materials, University of Wollongong, Northfields Avenue, Wollongong, NSW 2500, Australia.
Frederick S
FS
Wells
Institute for Superconducting and Electronic Materials, University of Wollongong, Northfields Avenue, Wollongong, NSW 2500, Australia.
Alexey V
AV
Pan
Faculty of Science and Technology and MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
X Renshaw
XR
Wang
Institute for Superconducting and Electronic Materials, University of Wollongong, Northfields Avenue, Wollongong, NSW 2500, Australia.
Sergey A
SA
Fedoseev
Faculty of Science and Technology and MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Hans
H
Hilgenkamp