Microstructure and superconducting properties of Y--Ba--Cu--O and Yb--Ba--Cu--O thin films formed by metalorganic deposition

Thin films of Y--Ba--Cu--O and Yb--Ba--Cu--O, 0.5--1.5 μm in thickness, were deposited onto left-angle 211 right-angle and left-angle 100 right-angle SrTiO3 single crystal substrates by metalorganic deposition (MOD). After deposition the samples were annealed by conventional furnace annealing or rapid thermal annealing (RTA). The microstructures of these films were then characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive x-ray spectrometry (EDS). Grain size of the annealed films varied from 0.25 to 1.0 μm. Improved superconducting properties were found for the RTA samples, compared to furnace annealing, and were attributed to larger grain size, little strontium diffusion into the thin films from the substrate, and highly preferred orientation of the 1:2:3 phase