The activation energy in several (YBCO)m/(PBCO)n superconducting multilayers was deduced from resistivity measurements in magnetic fields up to 16 T, as a function of the angle between the magnetic field and the ab planes. The activation energy U0(B,θ) scales with a reduced field Bred=B(sin2 θ+cos2 θ/Γ2)1/2, with an angle dependent anisotropy parameter Γ. A crossover from U0∝log Bred, at low Bred, to U0∝(Bred)α at high Bred, is also observed. The implications of these results on vortex dynamics and on the coupling between the superconducting layers will be discussed.
|Number of pages||5|
|Journal||Journal Of Low Temperature Physics|
|Publication status||Published - 1 Dec 1999|