Thermal fluctuations in the electric conductivity of YBa2Cu3O7¡d superconducting thin films grown on
Sr2YSbO6 novel substrate materials in the film form were experimentally studied. YBa2Cu3O7¡d 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(2) A° . The YBa2Cu3O7¡d thin
films, grown on Sr2YSbO6 films, exhibit an oriented growth in the (001) crystallographic direction, with lattice
constant c=11,65(9) A° . Morphological characterizations were performed by means atomic force microscopy.
Experiments of electrical resistivity show that the YBa2Cu3O7¡d films present a normal-superconducting transition
with critical temperature Tc=82,33 K. Fluctuation analysis for the YBa2Cu3O7¡d 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 lCR=0,35 were obtained close to Tc. This critical regime is effectively
described by the 3D-XY model.
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