We report on the angular dependence of the magnetoresistance in YBCO/PBCO m
ultilayers with thick PBCO layers, in magnetic fields up to 16T and with an
angular resolution of 0.01 degrees. From these measurements, the anisotrop
y parameter was extracted, presenting an unexpected field and angle depende
nce. These results are interpreted as a consequence of vortex shape effects
in the thin decoupled YBCO layers. (C) 2000 Elsevier Science B.V. All righ
ts reserved.