[en] The UK-SERC synchrotron at the Daresbury Laboratory, known as the ''SRS'' and operational since 1981, is dedicated to the study of various kinds of biological and inorganic materials. This paper outlines its potential benefits to ceramics research, particularly the application of synchrotron powder diffraction techniques. Of these, dynamic (or time-resolved) powder diffraction using the energy-dispersive mode has been used to study the synthesis of several kinds of ceramics, notably clay-based ceramics, zirconia, cements and zeolites. Examples from these studies are given. (Author)

[en] We have studied the local transport properties in an epitaxial YBa₂Cu₃O_7-x (YBCO) film on LaAlO₃ (LAO) using variable temperature scanning laser microscope (VTSLM) near the superconducting transition. A map of the superconducting transition temperature (T_c^*) is generated from a series of VTSLM images. The map of T_c^* indicates there are inhomogeneities in the film large enough to create nonuniform current flow near the superconducting transition. The evaluated T_c^* varies between 90.3 and 91.0 K in the film. Even though such change in T_c^* is not large enough to be detected by other localized compositional and structural characterization techniques, this along with an area of lower T_c^* and/or higher resistance affects current flow near the superconducting transition temperature as shown in VTSLM images. This inhomogeneity may be caused by slight variations of the stoichiometry and/or oxidation of the YBCO film

[en] We consider the distribution of an electric field in YBa₂Cu₃O_7-x (YBCO)-coated conductors for a situation in which the DC transport current is forced into the copper stabilizer due to a weak link-a section of the superconducting film with a critical current less than the transport current. The electric field in the metal substrate is also discussed. The results are compared with recent experiments on normal zone propagation in coated conductors in which the substrate and stabilizer are insulated from each other. The potential difference between the substrate and stabilizer, and the electric field in the substrate outside the normal zone, can be accounted for by a large screening length in the substrate, comparable to the length of the sample. During a quench, the electric field inside the interface between YBCO and the stabilizer, as well as in the buffer layer, can be several orders of magnitude greater than the longitudinal macroscopic electric field inside the normal zone. We speculate on the possibility of using microscopic electric discharges caused by this large (∼kV cm^-1) electric field as a means to detect a quench

[en] This paper reviews the current status of high temperature superconductor (HTS) based superconducting magnetic energy storage (SMES) technology as a developmental effort. Discussion centres on the major challenges in magnet optimization, loss reduction, cooling improvement, and new development of quench detection. The cryogenic operation for superconductivity in this technological application requires continued research and development, especially with a greater engineering effort that involves the end user. For the SMES-based technology to more fully mature, some suggestions are given for consideration and discussion. (paper)

[en] A two-dimensional model is introduced that describes DC current sharing between the superconducting and normal metal layers in a configuration typical of YBCO-coated conductors. The model is used to compare the effectiveness of a surround stabilizer and a more conventional one-sided stabilizer. When the resistance of the interface between the superconductor and the stabilizer is low enough, the surround stabilizer is less effective than the one-sided stabilizer in stabilizing a hairline crack in the superconducting film

[en] A second generation of the Rapid readout electronics has been designed, built and commissioned at Daresbury Laboratory. The first application is for a 1D small- and wide-angle scattering X-ray detection system on the new multipole wiggler 6.2 beam-line at the SRS. The ADC per channel system interpolates and yields typically 32 pixels per channel. The wide-angle detector uses 128 channels of electronics to produce 4096 pixels with a FWHM of four pixels, i.e. demonstrates an ability to resolve 1024 peaks across the detector. This corresponds to an FWHM of 400 μm over a 384 mm long (60 deg. ) curved detector. A second group of 128 channels instrument the 200-mm-radius quadrant detector for simultaneous small-angle scattering measurements. System rate of over 2x10⁷ events/s for each detector is predicted. A description of the new pipelined digital processing of detected events is given, together with initial beam-line test results

[en] Copper and Cu-Fe (Fe ∼2.35 wt%) alloy substrates were thermo-mechanically processed and the biaxial texture development, magnetic properties, yield strength, and electrical resistivity were studied and compared to determine their suitability as substrates for high-temperature superconducting coated conductor applications. Average full width half maximum (FWHM) of 5.5⁰ in Phi scans (in-plane alignment), and 6.6⁰ in omega scans (out-of-plane alignment) was obtained in copper samples. Cu-Fe samples showed 5.9⁰ FWHM in Phi scans and 5.9⁰ in omega scans. Even with the presence of 2.35% Fe in the Cu-alloy, the saturation magnetization (M_sat) value was found to be 4.27 emu g^-1 at 5 K, which is less than in Ni samples by an order of magnitude and comparable to that of Ni-9 at.% W substrates. The yield strength of the annealed Cu-Fe alloy substrate was found to be at least two times higher than that of similarly annealed copper substrates. The electrical resistivity of Cu-Fe alloy was found to be an order of magnitude higher than that of pure copper at 77 K

[en] We present a finite-element model for computing current and field distributions in multifilamentary superconducting thin films subjected to simultaneous effects of a transport ac current and a perpendicularly applied dc field. The model is implemented in the finite-element software package COMSOL Multiphysics and this solves Maxwell equations using a highly nonlinear resistivity to describe electrical superconducting characteristics. The time-dependent magnetic flux, current distributions, and ac losses are studied for different distances between filaments. We find that increasing the interfilamentary distance affects the transport and screening current distributions, reducing both the magnetic coupling and ac losses.

[en] The objective of this study was to examine the transport properties of two YBa₂Cu₃O_7-δ thin films with (Y_0.9Ca_0.1)₂BaCuO₅ additions deposited on vicinal SrTiO₃ 6⁰ bi-crystal substrates and to investigate the possible correlations between spatial calcium distribution and local electromagnetic properties across bi-crystal grain boundaries using evanescent microwave microscopy (EMM) and atomic force microscopy (AFM). The samples under consideration differed in transport critical current measurements by a factor of two although they were deposited on the same type of bi-crystal substrate. A near-field evanescent microwave microscope based on a coaxial transmission line resonator with an end-wall aperture was used to measure changes in conductivity local to the bi-crystal boundary of YBa₂Cu₃O_7-δ thin films below (79.2 K) and above (room temperature) the superconducting transition temperature. Atomic concentration measurements by electron microprobe analysis were performed in the same regions, and a clear correlation between calcium distribution and conductivity at 79.2 K (as represented by the change in quality factor) was found. Surface potential imaging (SPI) and quality factor scans in the area of the bi-crystal grain boundaries were performed at room temperature using AFM and EMM, respectively, to evaluate local electromagnetic properties in the normal state and investigate their correlation with superconducting properties

[en] Biaxially cube textured polycrystalline Cu(200) substrate tapes were produced for high temperature superconducting (HTS) coated conductor applications. A comparison is made between Cu substrates fabricated by reverse cold rolling followed by recrystallization, from stock materials that were obtained in the form of extruded rod and rolled plate. Detailed x-ray diffraction (XRD) studies and orientation imaging microscopy (OIM) were performed to measure the in-plane alignment, out-of-plane alignment, and microtexture at various deformation levels and annealing temperatures. The rod starting geometry proved to have superior biaxial alignment with a predominant (220) deformation texture after rolling. Phi (Φ) scan and psi (Ψ) scan XRD reveals that the best in-plane and out-of-plane alignment, measured in terms of full width half maximum (FWHM) values of 5.4 deg. and 5.8 deg., were obtained at 99.5% reduction in thickness and 750 deg. C annealing temperature. OIM microtexture results indicate that more than 97.5% of grains had less than 10 deg. misorientation with no observable twinning