OPTICAL AND TRANSPORT MEASUREMENTS ON YBA2CU3O6-FILMS LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-1)(X THIN)

We report optical reflectivity and transmission measurements at room t emperature on a set of five YBa2Cu3O6+x films for 0.38 less than or eq ual to x less than or equal to 1, and rho(T) resistivity data down to 10K, prepared from a single YBa2Cu3O7 thin film. In contrast with x=1, as x decreases, die scattering rate deduced from the optical conducti vity departs from its linear variation with omega, in correlation with the absence of linearity of rho(T) versus temperature.