TRANSPORT-PROPERTIES OF OXYGEN-DEFICIENT YBA2CU3O7-X THIN-FILMS

We report on measurements of the in-plane resistivity rho and Hall coe fficient R(H)(B \\ c) of various oxygen-deficient epitaxial films of Y Ba2Cu3O7-x in the normal state. The superconducting transition tempera tures T(c) of the samples vary from 14 to 90 K. Both the resistivity a nd the Hall coefficient exhibit a strong dependence on the oxygen cont ent and the temperature. As x increases, T(c) decreases continuously, while rho and R(H) gradually increase in magnitude. Furthermore, also the characteristic linear dependences of rho proportional-to T and R(H ) is-proportional-to T-1 of the highly doped compounds changes to a no nlinear behavior for the samples with T(c) lower than 60 K. The unusua l doping and temperature dependence of R(H) will be compared to the pr edictions of our calculations, based on a two-dimensional tight-bindin g model using the relaxation-time approximation. The model considers a lso the next-nearest-neighbor hopping, which strongly influences the p redicted Hall coefficient. Additionally, the cotangent of the Hall ang le cot(THETA(H)) is discussed in the framework of the two-dimensional Luttinger liquid theory.