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High current YBa2Cu3O7−δ (YBCO) thick films on flexible nickel substrates with textured buffer layers were fabricated. Highly textured yttria-stabilized-zirconia buffer layers were deposited by using ion beam assisted deposition (IBAD). Pulsed laser deposited YBCO films were not only c-axis oriented with respect to the film surface but also strongly in-plane textured. The in-plane mosaic spread of YBCO films was ∼10°. A critical current density of 8×105 A/cm2 was obtained at 75 K and zero field for thin YBCO films. It was also demonstrated that thick YBCO films with a high critical current and excellent magnetic field dependence at liquid nitrogen temperature can be obtained on flexible nickel substrates by using the textured buffer layers. The result indicates that thick film technology in combination with IBAD buffer layers could be a viable method for fabricating YBCO tapes in long lengths.

Phase and amplitude perturbations (trimpis) on VLF signals propagating in the earth‐ionosphere waveguide are usually explained in terms of precipitation‐induced modification along the great circle path as though it were a one‐dimensional (1‐D) waveguide. The alternative 2‐D view presented here is that precipitation‐induced ionization patches, laterally displaced from the great circle path, produce echoes at the receiver slightly delayed relative to the direct signal. Interference between the direct and echo signals can produce both phase and amplitude trimpis of both signs. Single‐mode propagation is assumed here, since it is likely that the second mode amplitude exceeded that of the first by ∼12 dB. We apply this theory to a sequence of trimpis observed on the North West Cape (NWC)‐Dunedin path on July 10, 1987. This indicates a north–south drift of the precipitation region consistent with drift speeds of whistler ducts. The theory is also applied to events published in the literature.

The results of Monte Carlo simulation of phase separation during binary film coevaporation are presented for a range of deposition conditions. The model employed assumes that phase separation occurs through surface interdiffusion during deposition, while the bulk of the film remains frozen. Simulations were performed on A-B alloy films having compositions of 10 and 50 ~01% solute. For both film compositions, the lateral scale of the domains at the film surface evolves to a steady-state size during deposition. A power-law dependence of the steady-state domain size on the inverse deposition rate is obtained. Simulation microstructures at 50 vol % compare favorably with those obtained in a previous experimental study of phase separation during coevaporation of Al-Ge films of the same composition. Results of simulations performed at 10 ~01% are compared with the predictions of a. theoretical model based on the above assumptions. The power-law exponent obtained from simulations at 10 ~01% is different than that predicted by the theoretical model. The reasons for this difference are discussed.

Conductive SrRuO 3 thin films were epitaxially grown on (100) LaAlO 3 substrates by pulsed laser deposition over a temperature range from 650 ± C to 825 ± C. Well-textured films exhibiting a strong orientation relationship to the underlying substrate could be obtained at a deposition temperature as low as 450 ± C. The degree of crystallinity of the films improved with increasing deposition temperature as confirmed by x-ray diffraction, transmission electron microscopy, and scanning tunneling microscopy. Scanning electron microscopy revealed no particulates on the film surface. The resistivity of the SrRuO 3 thin films was found to be a strong function of the crystallinity of the film and hence the substrate temperature during film deposition. A residual resistivity ratio (RRR r 300 K ͞r 4.2 K ) of more than 8 was obtained for the SrRuO 3 thin films deposited under optimized processing conditions.