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The thickness dependence of critical current density (Jc) has been investigated in YBa2Cu3O7-x films with BaZrO3 (BZO) nanorods (YBCO/BZO) aligned along the film normal. With the presence of linear defects in the YBCO/BZO films, the thickness dependence of Jc becomes negligible at self field and weak applied magnetic field (H), suggesting these linear defects playing a key role to the elimination of the thickness dependence of Jc. The effect of temperature (T) and H on Jc thickness dependence have been investigated and comparisons have been made between YBCO and YBCO/BZO samples. Since BZO nanorods alignment is greatly influenced by growth temperature, the quantitative difference in terms of nanorod's density and average length is reflected on Jc angular dependence of H and Jc thickness dependence as thermally assisted flux motion (TAFM) becomes important above a threshold H determined by the BZO nanorod density. With further increasing H, a monotonically increasing Jc vs. thickness trend was observed in YBCO/BZO films, in contrast to an opposite trend when collective pinning is dominant. This result suggests the thickness dependence of Jc is dictated by the microstructure and hence pinning mechanism in YBCO films. [ABSTRACT FROM AUTHOR]

We report on the effects of different multifilamentary geometries on the dynamic current and field distributions in YBa2Cu3O7-δ thin films. Finite-element model simulations are presented that allow a direct comparison of the calculated magnetic flux and current profiles with experimental data obtained by time-resolved magneto-optical imaging. We find that increasing the distance between filaments reduces the magnetic coupling and decreases the ac losses. Screening and transport currents also redistribute more evenly between all filaments. The measured transport current density profiles are in good agreement with the modified critical state model. [ABSTRACT FROM AUTHOR]

Multifilamentary coated conductor (MFCC) samples with patterned links have been studied using transport and scanning laser microscopy (SLM) techniques. Striation patterns are fashioned to define multiple filaments with discretely placed superconducting (SC) links between the filaments for current sharing and redistribution. After initial measurements, an artificial incision is made on a filament to mimic a disabled filament. The changes in global and local current transport characteristics are noted for in terms of the redistribution of current flow and the modification of local dissipation. Our results show that the patterned links between filaments play a vital role in redistributing current and encouraging current sharing. We find that the main factors in limiting the current-carrying capability of MFCC samples are local current density increases, which we call “current crowding.” The susceptible areas for current crowding are several: (1) filaments adjacent to the disabled ones, since the intact filaments have to carry extra current, (2) the links where current redistribution occurs, and (3) the partially blocked filament. [ABSTRACT FROM AUTHOR]

A simple investigation into the properties of weakly linked filaments in striated YBa2Cu3O7-d (YBCO) coated conductors has been performed. Such weak-link connections may arise in two different contexts within the coated conductors, the one case being the occurrence of unintentional connections. However, it may be desirable to intentionally induce the weak-link connections in order to allow a current sharing between the filaments. This allows the localized degradation of a given filament to be circumvented at a small cost in terms of the added losses and magnetization. This problem has been treated mathematically with a comparison of the superconductor weak linking in contrast to the normal-metal-induced current sharing. The estimates for target values of filament coupling are deduced, and the results in terms of magnetization are then determined. The YBCO samples created, using the pulsed laser deposition, are described that have these properties. The samples consist of one control and one striated sample. The magnetization response of these samples is then considered in terms of the expressions developed. [ABSTRACT FROM AUTHOR]

Presents a study which showed that radio frequency (rf) excited discharges of xenon (Xe) and I2 mixtures may provide multiwave length ultraviolet (UV) lighting sources, by using absorption and emission spectroscopy. Details on the gas kinetics of rare gas/ halogen mixtures; Role of ion-ion neutralization in the steady state discharge for high power inductively coupled discharges.

Presents a study which investigated low pressure radio frequency inductive discharges sustained in Xe/I[sub2] mixtures for production of ultraviolet radiation from XeI at 253nm. Overview of the kinetics of Xe/I[sub2] discharges; Description of the experiment; Experimental results for excited state emission and absorption in Xe/I[sub2] discharges; Conclusions.

A Monte Carlo simulation of liquid water near a charged wall has been carried out for different values of the surface charge density. The surface excess of electric potential as a function of charge density has been determined from the polarization profiles. The differential capacity of the simulated system is compared with the differential capacity of the mercury/water interface. [ABSTRACT FROM AUTHOR]

Presents a study that investigated friction and wear of plasma-deposited diamond films. Experimental procedures for the preparation of the diamond films; Conditions of friction and wear experiment; Characterization of diamond films.

We report the results of an experimental study of a persistent coil made out of YBa2Cu3O7-δ coated conductors. The magnitude of the persistent current and the rate of decay were investigated. Two distinct modes of relaxation are evident—one is flux creep and the other, which is much faster, is of less obvious origin. Our conclusion is that the persistent current in such a coil can be large enough and decay slowly enough so that coated conductors can be used to make persistent coils for variety of applications. [ABSTRACT FROM AUTHOR]

Magnetization results of YBa2Cu3O7-d films processed with interlayers of CeO2 inclusions are presented. Unexpected flux pinning results that are different from previous observations with nanoparticulate layered inclusions were observed. Flux pinning was found to be in some cases either slightly improved at either low fields <0.5 T or in other cases at high fields >8 T although degraded, sometimes severely, at interim magnetic fields. Most unexpectedly, the pinning performance of the various samples rapidly converges as the temperature is reduced from 77 to 65 K, causing all films to have similar Jc(H) behavior at 65 K even though dramatically different at 77 K. [ABSTRACT FROM AUTHOR]

Magnetization results of YBa2Cu3O7-d films processed with interlayers of CeO2 inclusions are presented. Unexpected flux pinning results that are different from previous observations with nanoparticulate layered inclusions were observed. Flux pinning was found to be in some cases either slightly improved at either low fields <0.5 T or in other cases at high fields >8 T although degraded, sometimes severely, at interim magnetic fields. Most unexpectedly, the pinning performance of the various samples rapidly converges as the temperature is reduced from 77 to 65 K, causing all films to have similar Jc(H) behavior at 65 K even though dramatically different at 77 K. [ABSTRACT FROM AUTHOR]

Examines the nucleation and growth of diamond on pretreated silicon substrates. Use of microwave plasma enhanced chemical vapor deposition technique; Density average of diamond nucleation; Result of diamond deposition without pretreatment.