Storage and release of self-field-generated vortices in percolative YBa2Cu3O7-delta films

Pulsed-laser heating of current-biased percolative YBa2Cu3O7-delta films ca n be used to generate and release self-field-induced vortices. A laser puls e yields a voltage signal due to penetration of bias-current-induced magnet ic flux in absence of an external magnetic field. Upon recooling, strongly pinned vortices remain in the film. These remanent vortices have been detec ted after disconnecting the bias source in the currentless film. Applying a subsequent second laser pulse again yields a signal voltage but of opposit e sign due to magnetic flux redistribution. This phenomenon could be applie d as write-read memory. (C) 2000 American Institute of Physics. [S0003-6951 (00)01450-9].