R. Prozorov et al., ANGULAR ANISOTROPY OF THE IRREVERSIBILITY LINE IN THIN YBA2CU3O7-DELTA FILMS - PINNING IN VORTEX LIQUID, Czechoslovak journal of Physics, 46, 1996, pp. 1535-1536
We report on measurements of die angular dependence of the irreversibi
lity temperature T-irr(theta) in YBa2Cu3O7-delta films. We find that n
either depinning nor melting are responsible for the appearance of mag
netic reversibility. Instead, we find evidences that T-irr is determin
ed by a crossover from pinned to unpinned vortex liquid.