Scanning Hall probe microscopy has been used to make a microscopic study of flux structures and dynamics in yttrium barium copper oxide thin-film disks containing a regular $10\text{−}\mu \mathrm{m}$-period square array of $2.5\text{−}\mu \mathrm{m}$-sized holes (antidots). Images obtained after field cooling the sample to $77\mathrm{K}$ in very low fields reveal that the holes can trap two flux quanta at this temperature. Scans obtained after zero-field cooling (ZFC) to $77\mathrm{K}$ and a subsequent applied field cycle clearly display preferential flux channeling along chains of antidots in the direction of maximum induction gradient. Remarkably, upon reversal of field sweep direction, we observe flux “streaming” out of the holes towards the sample edges with almost uniform density flux “stripes” bridging the holes in the exit direction. We estimate that the antidots can preferentially trap about 15 flux quanta in these ZFC experiments. Classical electrodynamics simulations of our samples appear to be in good qualitative agreement with our results, indicating that many of the observed phenomena may be geometrical effects that depend primarily on the shape and topology of the sample, and potential applications are discussed.

• Received 21 November 2003

DOI:https://doi.org/10.1103/PhysRevB.71.144504