Relaxation of transport current distribution in a YBaCuO strip studied by magneto-optical imaging

Abstract

The dynamics of magnetic flux distributions across a YBaCuO strip carrying\ntransport current is measured using magneto-optical imaging at 20 K. The\ncurrent is applied in pulses of 40-5000 ms duration and magnitude close to the\ncritical one, 5.5 A. During the pulse some extra flux usually penetrates the\nstrip, so the local field increases in magnitude. When the strip is initially\npenetrated by flux, the local field either increases or decreases depending\nboth on the spatial coordinate and the current magnitude. Meanwhile, the\ncurrent density always tends to redistribute more uniformly. Despite the\nrelaxation, all distributions remain qualitatively similar to the Bean model\npredictions.\n