We report on the scaling relation between the Hall and longitudinal resisti
vities, rho(H) proportional to rho(beta), in an unidirectionally twinned YB
CO thin film, for current flowing parallel and perpendicular to the twin bo
undaries for high magnetic fields. Our results are discussed in the framewo
rk of existing models for anisotropic pinning. (C) 2000 Elsevier Science B.
V. All rights reserved.