LOW-ANGLE DEVIATION FROM THE ANISOTROPIC EFFECTIVE-MASS MODEL IN EPITAXIAL YBA2(CU1-XZNX)3O(7-DELTA) THIN-FILMS

The magnetic field effect on the electrical in-plane resistivity rho(a b) has been investigated for high quality c-axis oriented YBa2(Cu1-xZn x)(3)O7-delta thin films (x=0.02 and 0.04) by magnetoresistance measur ements up to 20 Teslas for different orientations of the magnetic fiel d with respect to tile a-b plane, at different temperatures below T-c. Deviation in the scaling behaviour expected from tile anisotropic eff ective mass model is observed for small misalignement between the magn etic field direction and the superconducting CuO2 planes, which is att ributed to the intrinsic pinning effect. The Zn doping influence on th e anisotropic ratio gamma = xi(ab)/xi(c) is Studied from the high angl e scaling properties of the film.