Memory effects in the dynamics of the vortex lattice in YBCO crystals; the role of correlated defects

G. PASQUINI, D. LUNA, G. NIEVA AND V. BEKERIS

REVISTA MEXICANA DE FíSICA

Asociacion Mexicana de Fisica

Lugar: Mejico; Año: 2007 vol. 53 p. 50 - 52

0035-001X

Memory effects (ME) in the solid vortex lattice (VL) are observed in a wide range of superconducting materials. Experiments in twinnedY Ba2Cu3O7 (YBCO) crystals in a DC magnetic field tilted respect to the twin planes indicate that ME in these samples cannot beascribed to an equilibration process. However, how extensive is this behaviour, has not been explored so far. In this work we studythe role of correlated defects in ME by performing angular ac susceptibility measurements in YBCO crystals. We conclude that, whenuncorrelated disorder prevails, either in twinned or untwinned samples, ME have their origin in the oscillatory character of the vortexdynamics.