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Thin film materials with a giant dielectric permittivity er′≈10 000 and an electromechanical strain of Δh/h≈8% are produced by pulsed-laser deposition. Composite targets containing various different oxides such as BaTiO3, BaO2, BaCO3, and TiO2 powder embedded in the polymer polytetrafluoroethylen (PTFE) are employed for laser ablation. The dielectric permittivities of the films show strong relaxation at frequencies above 10 kHz, a pronounced dependence on layer thickness, and a frequency-dependent activation at lower temperatures. Composite targets as well as films produced from BaF2/PTFE targets show only low permittivities with er′

Vicinal YBa2Cu3O7?? (YBCO) thin films of thickness h = 20–480?nm are grown by pulsed-laser deposition on 10° miscut (001) SrTiO3 substrates. The anisotropic resistivities, c-axis texture, and critical temperature drastically depend on the thickness of vicinal films. High-resolution electron microscopy reveals a defect microstructure with strong bending of the YBCO lattice near the SrTiO3 interface and improved film microstructure at larger distances to the substrate. The required layer thickness for microstructure relaxation and increase of electrical conductivity are significantly larger than the critical thickness of c-axis oriented YBCO films.

Critical current measurements for varying angles of applied field have been performed on Bi2Sr2CaCu2O8 thin films grown on 10° vicinal (001) substrates. Measurements were performed on current tracks orientated both parallel (L) and transverse (T) to the vicinal steps. No Josephson vortex channeling effect was observed, in contrast to results previously obtained on both oxygenated and deoxygenated YBa2Cu3O7−δ films grown on vicinal substrates. In addition, no force-free peak was observed when the applied field was parallel to the current. This provides experimental evidence that there is a difference between the pancake coupling mechanism in YBa2Cu3O7−δ at small field angles where Josephson vortices are present and that in Bi2Sr2CaCu2O8.

High quality thin films of oxygen-depleted YBa2Cu3Ox (x≈6.6) were prepared by pulsed-laser deposition on SrTiO3, substrates that were cut with tilt angles of 10° and 20° with respect to the [001] direction, resulting in a steplike growth of the layers. The resistance showed a semiconducting behavior along the projection of the c axis to the film surface, but a metallic behavior in the perpendicular direction, indicating that the former is dominated by the c-axis resistivity and the latter by the ab-plane resistivity of YBa2Cu3Ox. Long-term illumination of the samples with a 100 W halogen lamp resulted in a significant conductivity enhancement in both directions. The photoinduced change of the out-of-plane resistance vs temperature characteristics is comparable to the effect of large hydrostatic pressure, introducing structural changes similar to that of photoexcitation.

Thin epitaxial films of gallium orthophosphate (GaPO4) are grown on α-quartz (SiO2) substrates. Here, amorphous stoichiometric precursor layers fabricated by pulsed-laser deposition on (001) SiO2 substrates are transformed to crystalline GaPO4 by postannealing in air at 650–950°C. Epitaxial films with thicknesses up to 300nm exhibit strong in-plane and out-of-plane textures (angular widths