SYSTEMATICS OF FLUX JUMPS AND THE STABILIZING EFFECT OF FLUX CREEP IN A LA1.86SR0.14CUO4 SINGLE-CRYSTAL

Flux jumps have been observed in a large (138 mg) single crystal of La1.86Sr0.14CuO4. Both complete and incomplete flux jumps are observed with the energy dissipated by complete flux jumps consistent with temperature rises to nearly T(c). The systematics of these flux jumps with respect to field history, temperature and the time duration of the hysteresis measurements are reported. The field at which flux jumps first occur and their subsequent spacing are not consistent with a simple adiabatic theory of flux jumps for our experimental conditions. Instead, the crystal is observed to be stabilized against flux jumps by flux creep which occurs during the time interval over which field steps are accomplished as well as during imposed time intervals between field steps.