Current distribution of collective thermal depinning of Josephson vortices in naturally stacked Josephson junctions

Abstract

We investigated the thermal-depinning current (I(c)) distribution of Josephson vortices (JVs) in naturally stacked Bi(2)Sr(2)CaCu(2)O(8+delta) intrinsic Jospehson junctions in tesla-range magnetic fields and at different field tilt angles from the in-plane position. The I(c) distribution in the thermal-activation regime contains accurate information on the bias and magnetic-field dependence of the Josephson-vortex pinning potential. In a few-tesla-range magnetic field, JVs in a row in a junction, strongly coupled with each other, are pinned or depinned like a single physical entity at a single pinning center. In the best-aligned in-plane magnetic field, the edge pinning is most relevant and is insensitive to the field strength. In the presence of pancake vortices (PVs) in a slightly tilted field, however, the PV pinning deepens the JV pinning potential linearly with the number of PVs.