Abstract :
Epitaxial Pr1−xCaxBa2Cu3O7−y (0≤x≤0.5) thin films were deposited on SrTiO3 and YSZ substrates by PLD at different temperatures. Short and long range order in the crystalline structure as well as the direction of crystal growth on the substrate, being relevant issues in the transport properties of the material, were studied by scanning (SEM) and transmission (TEM) electron microscopy as well as X-ray diffraction (XRD) for their microstructure characterization. XRD and TEM studies revealed epitaxial growth on YSZ substrates (for 0≤x≤0.3) along a and c axis at temperatures of 550 and 600°C, respectively. For the films on SrTiO3 a preferential growth along c-axis was observed with a small fraction oriented along the a-axis at temperatures as high as 650°C. The four probe method was used to obtain the ρ vs.T curves, where a typical hopping conduction mechanism between localized states was observed.
