  We directly image individual vortex positions in nanocrystals in order to
unveil the structural property that contributes to the depletion of the
entropy-jump entailed at the first-order transition. On reducing the
nanocrystal size the density of topological defects increases near the edges
over a characteristic length. Within this "healing-length" distance from the
sample edge vortex rows tend to bend while towards the center of the sample the
positional order of the vortex structure is what is expected for the
Bragg-glass phase. This suggests that the healing-length may be a key quantity
to model the entropy-jump depletion in the first-order transition of
extremely-layered vortex nanocrystals.
