CURRENT-INDUCED RESISTIVITY SWITCHING EFFECTS NEAR THE MELTING LINE IN DETWINNED YBA2CU3O7-DELTA

Hysteresis of the E-J characteristics has been observed in the vicinit y of the melting line using a sensitive superconducting quantum interf erence device picovoltmeter with millikelvin temperature resolution. I t was found that in this region the system could be switched from a lo wer-to a higher-resistivity state by applying a current in excess of a threshold value. From the comparison of transport and ac susceptibili ty data, we conclude that in this hysteretic region the vortex solid a nd liquid phases coexist and that the observed transport phenomena can be explained in terms of the rearrangement of solidified vortex domai ns.