Dynamic stability of the vortex solid state of YBa2Cu3O7-delta single crystals

Investigations have been carried out on history dependences within the driv en vortex solid state of YBa2Cu3O7-delta single crystals. It has been demon strated that the driven system has the tendency to stabilise in two particu lar dynamic phases: one ordered, the other relatively disordered. Transient responses observed on switching between drive modulation forms were interp reted in terms of changeovers between these phases. An unusual oscillatory response, arising on application of an asymmetric drive, has been explained in terms of distinct regions of such phases coexisting within the sample, their relative proportions changing periodically with time. Specifically, i t has been demonstrated that the ordered dynamic state is inherently stable , in that it is easier to coherently drive an ordered-phase domain out of t he sample than it is to break it apart. (C) 1999 Elsevier Science B.V. All rights reserved.