Nadav Shapira has won at the 13th international workshop on vortex matter in superconductors  for the best poster on the Behavior of Individual Vortices on Twin Boundaries in Underdoped Single Crystal YBCO

I reported on measurements of individual vortices in YBCO single crystals with unidirectional twin boundaries (TBs) - a common planar defect in YBCO: Using low temperature magnetic force microscopy (MFM) with single vortex resolution we study the behavior of vortices in the vicinity of TBs. By imaging and dragging individual vortices we reveal their anisotropic behavior – it is easier to drag a vortex along a TB than across it, and observe a difference between dragging in the two directions normal to the TB. Finally, we search for variations of the superfluid density on TBs.

See attached figure:

A scan at T=4.8K  and at height ≈ 730 nm above the sample - vortices are visible as blue disks. We locate TBs by spatial correlations of vortex locations and by remembering that vortices decorate defects.