Published online by Cambridge University Press: 31 January 2011
We show that magnetic flux lattice interactions are important at fields above a few thousand gauss. These interactions interfere with thermally activated current-induced flux bundle hopping and reduce the superconductor's flux creep resistance below that estimated from the standard flux creep models (which assume completely independent hopping). We find that the flux bundles can hop independently at the low fields at which, e.g., antennas and SQUID detection coils would be used, but interact very strongly at fields typical of magnet applications.