Thermal fluctuations in the electric conductivity of YBa2Cu3O7 - delta superconducting thin films grown on Sr2YSbO6 novel substrate materials in the film form were experimentally studied. YBa2Cu3O7 - delta films were grown by using a dc-technique on Sr2YSbO6 substrates, which were produced by rf magnetron sputtering. X-ray diffraction analysis evidenced that the Sr2YSbO6 films grow on conventional SrTiO3 substrates in a preferential orientation along the (100) planes direction with lattice parameter a=4,43() Å. The YBa2Cu3O7 - delta thin films, grown on Sr2YSbO6 films, exhibit an oriented growth in the (001) crystallographic direction, with lattice constant c=11,65(9) Å. Morphological characterizations were performed by means atomic force microscopy. Experiments of electrical resistivity show that the YBa2Cu3O7 - delta films present a normal-superconducting transition with critical temperature Tc=82,33 K. Fluctuation analysis for the YBa2Cu3O7 - delta thin films were performed by utilizing the concept of logarithmic derivative of the conductivity excess. Above the critical temperature Tc we experimentally determine the occurrence of Gaussian 3D, 2D and fractal fluctuation regimes. A genuinely critical region identified by the exponent lambdaCR=0,35 were obtained close to Tc. This critical regime is effectively described by the 3D-XY model.