Anisotropic Jc-/spl thetav/ measurements at low fields on a-MoSi thin films: evidence of a two-dimensional regime

Transport critical current versus applied field inclination (Jc-/spl thetav/ plots) have been made on a-MoSi thin films in low fields of order 0.04 T. The applied field was rotated (at fixed magnitude) in a plane both parallel (/spl phi/=0/spl deg/) and perpendicular (/spl phi/=90/spl deg/) to the film's longitudinal axis. The results indicate a Jc governed by the perpendicular component of the applied field as is sometimes observed in the layered high-temperature superconducting (HTS) thin films. These results also suggest that the peaks in the Jc-/spl thetav/ occur when the vortex density coming from external sources becomes comparable to that induced internally from the self field of the transport current. A broad peak in the Jc when the field is incident perpendicular to the film surface is observed on the silicon substrate film but not on the sapphire substrate film. Possible reasons for this broad peak are discussed.