(Pb)(Zr(0.52)Ti(0.48))O(3) films were fabricated on LaNiO(3) (LNO)/ In(2)O(3) 90%SnO(2)10% (ITO) layered transparent electrodes on glass substrates, using chemical solution deposition. The electrical and optical properties of transparent ITO/LNO/PZT/LNO/ITO capacitors fabricated on glass substrates were studied. The remnant polarization (P(r)) of the transparent ITO/LNO/PZT/LNO/ITO/glass capacitors was determined from P-E hysteresis loops measurements. Excellent optical transmittance was observed for the whole capacitor structure. The importance of a high performance transparent capacitor is that this structure may enable a new generation of high efficiency transparent electronic devices such as solar energy storage, photovoltaic, and intelligent windows, among others.

( Pb ) ( Zr 0.52 Ti 0.48 ) O 3 (PZT) films were fabricated on LaNiO3 (LNO)/In2O3 90%SnO210% (ITO) layered transparent electrodes on glass substrates using chemical solution deposition. The structural, electrical, and optical properties of semitransparent Pd/PZT/LNO/ITO and transparent ITO/LNO/PZT/LNO/ITO capacitors fabricated on glass substrates were studied. X-ray diffraction revealed an improved crystalline structure of PZT on ITO-buffered glass substrates by interposing a LNO layer between PZT and ITO. Atomic force microscopy showed a smoother surface topography for the LNO/ITO layered electrode on glass, as compared to that of the single ITO layer on glass. The remnant polarization (Pr) of the Pd/PZT/LNO/ITO/glass capacitors and transparent ITO/LNO/PZT/LNO/ITO/glass capacitors was estimated from P-E hysteresis loops. The Pd/PZT/LNO/ITO capacitors on glass revealed significant improvement in the Pr as compared to PZT film based capacitors with ITO electrodes only. Excellent optical transmittance was observed for the whole capacitor structure. The importance of a high performance transparent capacitor is that this structure may enable high efficiency transparent electronic devices such as solar energy storage, photovoltaic, and intelligent windows, among others.

Biaxially textured MgO films were grown by inclined substrate deposition (ISD) as template layers for YBa2Cu3O7-x (YBCO)-coated conductors. The surface roughness of films deposited at different angles and with varying thickness was examined by atomic force microscopy. Results were correlated with the texture, measured by X-ray diffraction, to determine the optimal thickness and deposition angle.

YBa2Cu3O7−δ (YBCO) films were fabricated on SrRuO3 (SRO)-buffered MgO templates grown on Hastelloy C276 metallic substrates, on which the MgO layers had been deposited by inclined substrate deposition (ISD) using electron beam evaporation. YBCO and SRO films were deposited by pulsed laser deposition (PLD). ISD-MgO substrates fabricated with two different substrate inclination angles (α = 35° and 55°) were used to grow YBCO films. High transport critical current density, Jc = 1.4 × 106 A cm−2, has been measured at 77 K in self-field for YBCO film grown on ISD-MgO with α = 35°, whereas YBCO film grown on ISD-MgO with α = 55° had a lower Jc = 0.5 × 106 A cm−2. X-ray pole figure patterns revealed a cube-on-cube orientation relationship among YBCO, SRO, and ISD-MgO films, with the c-axis of the YBCO film being tilted. X-ray ω and ϕ-scans revealed good in-plane and out-of-plane textures of YBCO film grown on ISD-MgO substrate. The YBCO film grown on ISD-MgO with substrate inclination angle α = 35° had a YBCO(005) ϕ-scan full width at half maximum (FWHM) = 5.8° and a YBCO(007) ω-scan FWHM = 2.8°, while YBCO film with α = 55° had YBCO(005) ϕ-scan FWHM = 5.4° and YBCO(007) ω-scan FWHM = 2.6°.

YBCO-coated conductors with high current-carrying capability are desirable for electric power transmission applications. Inclined-substrate deposition (ISD) is capable of producing high-quality biaxially textured template films, which are important for fabrication of YBCO-coated conductors. We have grown biaxially textured ISD-MgO template films on flexible metallic substrates at deposition rates of 2-10 nm/sec. Columnar grains with a roof-tile-shaped surface structure were observed on the ISD-MgO films. X-ray pole figure analysis revealed that the ISD-MgO film is biaxially textured and its c-axis is titled at an angle from the substrate normal. Strontium ruthenium oxide (SRO) buffer films were epitaxially grown on ISD-MgO by pulsed laser deposition prior to the deposition of YBCO. Low /spl phi/-scan full-width at half maximum (FWHM) values of 6/spl deg/ and 7/spl deg/ were observed for YBCO and SRO, respectively. T/sub c/ of 91 K with a sharp transition and transport J/sub c/ over 1.4 MA/cm/sup 2/ at 77 K in self-field were measured on YBCO coated conductors grown with ISD MgO architectures using a SRO buffer.

Inclined substrate deposition (ISD) is an attractive technique for rapid production of high-quality template layers for YBCO-coated conductors. We have grown biaxially textured magnesium oxide (MgO) films on metallic substrates by ISD at rapid deposition rates, 20–100 A s−1. Scanning electron microscopy of the ISD MgO films showed columnar grain structures with a roof-tile-shaped surface. X-ray diffraction pole figure analysis revealed that the ISD MgO film is biaxially aligned with the c-axis tilted from its substrate normal. Tilt angles of and were measured on ISD MgO films deposited at 55° and 35° inclination angles, respectively. A full width at half maximum (FWHM) of was observed in the -scan for short-length ISD MgO films. A 1 m long tape of ISD MgO grown on a metallic substrate was fabricated by a reel-to-reel method. This tape has an average -scan FWHM of 16.1° with a standard deviation of 2.6°. YBCO films were grown on strontium ruthenium oxide (SRO)-buffered ISD MgO substrates by pulsed laser deposition. A superconducting critical transition temperature Tc = 91 K and critical current density Jc = 1.1 × 106 A cm−2 were measured at 77 K in self-field for a sample that is 0.3 µm thick, 2.9 mm wide, and 1.0 cm long.

The superconducting, crystalline, and morphological properties of YBCO films deposited on SrRuO3-buffered MgO substrates were studied at various deposition temperatures. The film deposited at T = 770 degreesC had the best superconducting properties (critical current density of 2.5 x 10(6) A cm(-2) and critical transition temperature of 91 K). Scanning electron micrographs of this film revealed uniform and well-connected grains. X-ray analyses revealed that the YBCO/SrRuO3/MgO film fabricated at 770 degreesC had good in-plane and out-of-plane textures. Raman spectroscopy showed that this film had the best out-of-plane texture and orthorhombic I domains.

We were able to vary the oxygen concentration of a YBCO coated-conductor sample from the under-doped to the over-doped regime. This was achieved by secondary oxygenation treatments at temperatures between 250°C and 500°C employing a novel oxygenation scheme. The YBCO-coated conductor was fabricated by the inclined substrate deposition method. Superconducting transition temperature and critical current as function of temperature and magnetic field were determined by a contact-free magnetization technique on a ring sample. It is observed that for temperatures at and below 77K, the maximum critical current is obtained in the most over-doped state where the transition temperature is significantly depressed.

Inclined substrate deposition (ISD) has great potential for rapid production of high-quality template layers for YBCO-coated conductors. We have grown biaxially textured magnesium oxide (MgO) films on metallic substrates by ISD at deposition rates, 20-100 Angstrom/s. Scanning electron microscopy of the ISD MgO films showed columnar grain structures with a roof-tile-shaped surface. X-ray diffraction and pole figure analysis revealed that the c-axis of the ISD MgO is tilted at an angle with respect to the substrate normal. A full width at half maximum (FWHM) of approximate to10degrees was observed in the phi-scan for MgO films. Yttria-stabilized zirconia (YSZ) and ceria (CeO2) buffer layers were epitaxially grown on ISD MgO by pulsed laser deposition (PLD) prior to YBCO deposition by PLD. The YBCO films grown on YSZ/CeO2 buffered ISD MgO substrates were biaxially aligned with the YBCO c-axis normal to the substrate surface. A critical current density of J(c) > 1.2 x 10(6) A/cm(2) was measured at 77 K in self-field. (C) 2003 Elsevier B.V. All rights reserved.

In this paper, we attempt to grow films on a MgO substrate using Pulsed Laser Ablation, and report on the effect of deposition conditions and post-deposition annealing on the film properties.

Magnetic hysteresis and magnetic relaxation measurements have been performed to study vortex pinning behaviors for pure, Fe doped and heavily Pb doped Bi2212 single crystals. Unlike pure and Fe doped Bi2212 crystals, heavily Pb doped crystal showed strong vortex pinning behavior. We interpret the strong pinning in heavily Pb doped Bi2212 single crystals as arising from the improved Josephson coupling in Bi2212 single crystal after heavy Pb doping. In heavily Pb doped single Bi2212 crystals, H-dis(T) was observed to decrease with increasing T. Here, H-dis(T) is an order-disorder field that separates a weakly elastically disordered vortex lattice from a plastically disordered vortex solid. However, in pure and Fe doped Bi2212 single crystals, H-dis(T) was observed to be temperature independent. We also report a significant shift of T-CR, a crossover temperature separating two pinning regimes, toward higher temperatures with heavy Pb doping of Bi2212 single crystals. On the other hand T-CR did not shift with Fe doping of Bi2212 single crystals. It is argued that the temperature dependence of H-dis(T) and the shift of T-CR in heavily Pb doped Bi2212 crystals was related to the enhanced c-axis conductivity caused by the Pb situated between the CuO2 layers and imposing a 3D characteristic on the vortex lattice.

The magnetic field H-dis(T) where an order-disorder transition of the vortex lattice in high-T-c superconductors occurs, is investigated by measurements of the magnetization M(H) in Bi2.1Sr1.9CaCu2O8+delta (Bi2212) single crystals doped with iron and lead. Comparative studies are made of the temperature dependences of the field H-peak(T), where the second peak occurs in \M(H)\, and the fields H-min(T), and H-infl(T) where a minimum and an inflection point occur at the low-field side of this peak. It is proposed that H-dis(T) lies close to H-infl. In Bi2.1Sr1.9Ca1.0(Cu1-yFey)(2)O8+delta single crystals with Fe concentration y=0, 0.005, 0.016, and 0.022, a pronounced peak in the derivative \dM/dH\ is observed, whose position H-infl(T) is independent of temperature T. We relate this peak to the field H-dis(T), which separates a weakly elastically disordered vortex lattice from a plastically disordered vortex solid. In heavily Pb-doped single Bi2212 crystals, H-infl(T) decreases with increasing T. For the same crystals, a minimum in the normalized relaxation rate S(H) is observed at H-infl, indicating two different flux-creep mechanisms above and below that field and two different solid vortex phases. It is argued that the negative slope of H-dis(T) in heavily-Pb-doped Bi2212 crystals is related to the enhanced c axis conductivity caused by the Pb sitting between the CuO2 layers and causing three-dimensional vortex lines, while in Fe-doped Bi2212 crystals the Fe ions sit on the CuO2 planes and thus do not enhance the coupling between pancake vortices.

Magnetic hysteresis loops and magnetic relaxation have been measured for pure and heavily lead-doped Bi2-xPbxSr2CaCu2Oy (Bi2212) single crystals. From the hysteresis loop measurements, the normalized critical current density Jc/Jc0 has been calculated, and from the relaxation measurements the activation energy, current-voltage curves and normalized relaxation rate have been obtained. The field and temperature dependences of Jc/Jc0 for Pb-doped crystals were much weaker than for the pure Bi2212 crystals. A large upward shift in the crossover temperature TCR, a temperature separating two different pinning regimes, has been observed for the first time with heavy lead doping. This was interpreted by improved inter-layer Josephson coupling of two-dimensional vortices, as a result of Pb doping. Heavily Pb-doped crystal had TCR = 35 K for the field that was within the secondary peak in its magnetic hysteresis loop. For pure Bi2212, TCR = 19 K.

We study the flux pinning of Bi2Sr2CaCu2O8+δ (Bi2212) single crystals doped with up to 2.2% of Fe on the Cu positions using measurements of magnetization hysteresis loop. We found that the critical current density increased with the doping for doping less than 0.5 at.%. This proves that Fe point defects contribute to the flux pinning. However, high doping levels deteriorate the Jc. The effect of Fe doping on the peak effect was also studied. The peak position shifts to high temperature, but the peak field decreased with increasing doping levels.

A comparative study of normalised flux creep rate S(T,H) for heavily lead doped Bi2212 single crystal and pure Bi2212 single crystal has been performed. A sharp anomaly in S(T) was observed at a temperature T = TCR, a cross over temperature below which collective pinning theory is valid for Bi2212 pure single crystal. Observed S(T) over a wide temperature range for the lead doped sample revealed a shift of TCR to a higher temperature. X-ray measurements showed a decrease of c-axis parameter with lead doping for this sample. The reduction of c-axis parameter improved the inter-layer coupling of the pancake vortices, enhancing the vortex pinning and causing the shift of the peak in S(T) towards a higher temperature. The critical current density Jc as a function of field also indicated strong pinning in the lead doped sample, as compared to pure Bi2212 single crystals.

Critical current density Jc as a function of magnetic field and temperature has been studied in Fe-doped and pure Bi2212 single crystals. The nominal iron content in the Bi2.1Sr1.9Ca1.0(Cu1-yFey)2Ox single crystal was y = 0.000, 0.005, 0.016 and 0.022. A strong field and temperature dependence of Jc has been observed for the samples with y = 0.022 and 0.016 doping. At zero field, large Jc was observed for these samples up to 40K, as compared to the samples with y = 0.005 and y = 0.000. However, for T > 40K, samples with y = 0.016 and 0.022 had lower values of Jc than samples with y = 0.000 and 0.005. Similarly, for H < 500Oe samples with y = 0.000 and 0.005 had lower Jc than the more strongly doped samples. For H > 500Oe, it was the opposite. The samples with y = 0.005 were found to show large Jc over a wider range of temperatures and fields than any other samples studied This indicated that the iron in the CuO2 planes acted as an effective pinning centre. The effectiveness of the pinning centres was strongly influenced by the field and thermal excitations.