We show that in a highly c-oriented 2:2:1:2 Bi-Sr-Ca-Cu-O film the angular-dependent magnetic field ${\mathit{H}}^{\mathrm{*}}$ at the onset of the resistivity behaves experimentally in a way completely analogous to the critical field found in synthetic multilayered superconductors. In particular, on varying the temperature, the field ${\mathit{H}}^{\mathrm{*}}$ exhibits a crossover from a 2D to an anisotropic 3D behavior as a function of the angle ϑ between the external magnetic field and the a-b plane.

• Received 2 April 1991

DOI:https://doi.org/10.1103/PhysRevLett.67.1795