Angular dependence of critical currents in Bi2Sr2CaCu2O8 thin films predominant role of the transverse magnetic field component
Résumé
We have studied the critical current of c-axis oriented Bi2Sr2CaCu208 thin films measured at various temperatures as a function
of magnitude (H_< 20 T) and orientation 0 (with respect to the c-axis) of the applied magnetic field. The curves J¢ (0) at a given
field H show a strong maximum when H is parallel to the CuO2 planes (0=90 ° ). For 0¢90 °, we show that J¢ depends only on
the component of the magnetic field along the c direction in the whole temperature range. In particular, at 4.2 K, J~(H, O) behaves
as [Hcos 01 -'~ with 0.44-< a < 0.5. These results agree with the recent scaling theory proposed by Blaner et aL describing the
behaviour of anisotropic superconductors for an arbitrary angle between the magnetic field and the anisotropic crystallographic
axis.