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The effect of substitution of various elements X for Hg on the growth and superconducting properties of (Hg,X)Ba2CunOy (HgX-12(n-1)n) has been studied. Results indicate that for X = V, Cr, Mn, Ge, Mo, Ru and Re, the formation of the phases of n = 2, 1, 2, 1, 3, 3 and 3, respectively, have been observed. The number n in the obtained HgX-12(n-1)n increased with increasing oxidation number of X. The substitution of X for Hg has been noted to stabilize the structures of HgX-12(n-1)n phases.

The study of the transport properties of the grain boundary was undertaken using more than a dozen successfully isolated, naturally-grown (100) tilt Bi2Sr2CaCu2O8+delta bicrystals. The bicrystals are characterized by a single clean (100) non-basal-plane-faced tilt grain boundary with various degrees of misorientation. The results showed that almost all the (100) non-basal-plane-faced tilt grain boundary had a T(sub c) depression as compared to the constituent single crystals. However, these grain boundaries did not behave like weak-links at low temperatures.

The experimental results of long Ag/Bi(Pb)-2223 multifilaments tapes showing I(sub c) versus length were presented. A contact-free method called the Hall probe was used to obtain the results. The method measured the shielding and remanent magnetic fields created by the tapes when exposed to an external magnetic field. The results showed that the method can be used to identify individual tapes by their signal pattern based on high reproducibility. In addition, spatial resolution was demonstrated to be as good as a few mm.

The current and field profiles in a finite cylindric type-II superconducting sample which result from displacing it within the magnetic field created by a coaxial permanent magnet were calculated. The minimization of the magnetic energy in the superconductor by means of introduction of currents with a maximum density following the critical-state model was the basis for the method of calculation. The effects of the superconductor finite size were fully incorporated in the calculations.

The non-destructive studies of superconductor homogeneity was conducted using a new generation of Hall sensor magnetometer. The measurement of the three-dimensional spatial dependence of all three components of magnetic field produced by applied or induced currents in the conductor is allowed by the magnetometer. Compared to the old Hall sensor techniques measuring only the field component perpendicular to the flat surface of the conductor, the new technique is more sensitive to detect small obstacles in the current path.

A scanning Hall probe was used to carry out direct local measurements of the characteristics of a mixed state induced by a magnetic field of a small ferromagnetic particle in thin film YBaCuO samples. The results showed evidence for an extremely low energy barrier for entry of vortex half-loops into high quality films. It was also observed that the half-loops further broke down into vortex-antivortex pairs which was consistent with the Josephson medium model.

Pulsed laser deposition on various single crystl substrates was used to fabricate epitaxial (rare earth)Ba2Cu3O7 films, RE123, with RE = Y, Er and Sm. Each material's deposition was optimized for T(sub c). An increase in ionic sized of the rare-earth element was observed in increased T(sub c) in RE123 films. In addition, the vortex pinning anisotropy was affected by the rare-earth element as shown by the study of field- and angle-dependent J(sub c).

The results of doping by ion implantation in YBCO films with five different ions were presented. The five ions are Ca, Na, Mg, Be and Li. The difference of ionic radii and heat of formation value served as the basis of ion selection. In the implantation process, ionic radii plays a critical role to crystal damage. Different doses of Ni ions were implanted to YBCO films to vary the resistance to the implanted film. Different values of Ni implanted structure resistance were then applied to the fabrication of chip resistors.

Two of the easiest superconducting thin films to grow are Tl-2212 and Tl-1212 in the unsubstituted Tl-Ba-Ca-Cu-O. Both phases exhibit smooth morphnologies and T(sub c) >95K, J(sub c)(5K)>10 MA/cm2. The properties of both films following one hour furnace anneals in dry ambients of pure oxygen or nitrogen were reported. The results showed that Tl-2212 films maintained their superconducting properties to even higher temperatures compared to Tl-1212 films. An increase in flux pinning was also noted in optimum annealing, although not on the same degree as for Tl-1212 films.

A system which allows simultaneous deposition of high temperature superconductivity (HTS) films on both sides of 3-inch wafers was constructed and described. A heating cavity where wafers are placed can be heated to 1000 degrees C. The use of inverted cylindrical magnetron sputtering guns enables the deposition through two opposite holes. A growth quality and T(sub c) and j(sub c) values comparable to standard films with sufficient uniformity on both sides of the wafer were revealed by YBaCuO films deposited on 3 inch CeO2 buffered substrates.

Research was conducted to examine the influence of superconducting energy gap on the performance of single electron transistor as electrometer. Its status was compared to that of a similar junction array made of normal metal, taking the superconducting energy gap into account. The charge transfer in the means of solitons introduced by the voltage source attached to the end of the array is described.

Research was conducted to examine the characteristics of the active loads based on the capacitively coupled HTSC-single hold transistor (HTSC-SHT) using a semi-classical model of the single hole tunneling effect. The characteristics were found to be different from that based on MOSFET due to the existence of the Coulomb blockade and energy gap of HTSC materials. Also investigated were the small signal equivalent circuit of the active loads.

Research was conducted to illustrate a compact superconducting/ferrite filter with useful tuning range and insertion loss. Magnetically tunable superconducting resonators and filters comprising microwave circuits coupled to ferrite substrates in monolithic structures using niobium at 4 K and hybrid resonator structures using YBCO at 77 K were demonstrated. The demonstration filter using niobium on ferrite can be extended to high-temperature superconducting materials such as YBCO in a straightforward manner.

Research was conducted to examine new microwave circuits for voltage standard application containing 256 bicrystal junctions. Results illustrate successful series dc and parallel ac biasing in such a meandered array. On each of the 8 subarrays, the first current step was achieved at liquid nitrogen temperature at a frequency f = 27332 MHz and for a constant microwave power. Possible ways to increase uniformity of the relative ac current and, correspondingly, the bias frequency were demonstrated.

Research was conducted to examine the properties of gold shunted bicrystal YBCO junctions on yttria-stabilized zirconia and sapphire substrates. Three important properties related to the problem of parameter spreads were noted. First was th control of the shunt resistance. SEcond was the impact of the shunt resistance and the spread in junction resistance on the tolerable junction size. Third was the realization of series arrays with a high packing density of junctions using electron-beam-patterning.

A three dimensional multichip modules technology was examined using high temperature superconducting thin films on stacked ceramic substrates. A simple, multilayer circuit was created to characterize the high-speed digital waveform characteristics and pulse integrity. Electrical tests were conducted before and after the cycling to determine circuit integrity. Results confirm a robust package with gigabit-per-second throughput capacity.

Semiconductor circuits operating in air at room temperature were imaged using a high temperature superconducting scanning superconducting quantum interference device (SQUID) microscope. The ability to locate a dead short to within about plus or minus 35 microns was demonstrated through the packaging of a microelectronic device at plus or minus 35 microns through the packaging of a microelectronic device at a distance of 150 microns.

The progress on the study of the behavior of axial and radial superconducting rotors powered by a classical copper wound armature is presented. Emphasis was on the magnetic field distributions around the rotor, magnetic interaction between inductor and superconducting rotor and static torque measurements. Results show that the exciting field generated by a conventional armature can be utilized to power a high temperature superconducting rotor generating not only the torque but also the bearing forces.

A series of studies that examine the operational properties of a high temperature superconducting synchronous motor of five to six hundred watts capacity are described. An experiment using ac 220V stator phase voltage and dc 4A excitation current and where the synchronous speed runs at 1800 rpm is discussed. A comparison of experimental results with theoretical predictions was carried out.

Research was conducted to examine the electrical and electromechanical behavior of the high temperature superconducting synchronous motor. High temperature superconducting field winding and one or more flux dampers were used for the rotor of a high temperature superconducting synchronous motor. Computer traces are provided to demonstrate the complete dynamic responses in several modes of operation.

The development of a 1-megawatt exciter/generator for airborne applications being developed by the US Air Force and Ballistic Missile Defense Organization is reported. The Air Force is currently investigating the potential for replacing the aluminum field coils with high temperature superconductor field coils cooled with hydrogen. The design, construction and testing of the field coils are discussed.

The conceptual design of the High Temperature Superconducting (HTS) generator for Mobile Radar applications is described. Its power system is composed of a generator, power conditioning electronics and a diesel engine. The cryogenic cooling of the generator and the power electronics result in substantial improvements in performance, system efficiency and power density. The total losses and efficiency are presented.

The progress of a project developed by the SuperTech Consortium in Hungary is described. Its objective is the design and construction of an experimental high temperature superconducting synchronous machine. The machine is excited with rare-earth permanent magnets on the rotor and rod-shaped armature conductors on the stator. The superconductor model involves the hysteresis and anisotropy of the material. Comparisons between high temperature semiconducting and conventional machines made for particular practical cases were performed.

The progress in the development of high efficiency high temperature superconducting motors is reported. The goals of the development project inslude saving half the losses of conventional motors in a package with half the volume. The status of a 1,000 hp motor development which is part of a Phase II effort is described. The motor fully represents the design issues to be addressed in the 5,000 hp motor also to be developed in Phase II.

Research was conducted to measure the transport current alternating current losses of different structures and different materials. Their dependence on the frequency and direct current background field was also examined. Results were compared with the Norris' elliptical and strip models. It was observed that there were discrepancies between the theoretical measurements and experimental data.

The paraconductivity of sputter deposited yttrium barium copper oxide thin film composites with cerium oxide and gold was investigated using the Aslamazov and Larkin theory. The superconducting transition properties and the paraconductivity of the composites were related to disorder and film morphology. Furthermore, the effects of film processing and storage on the paraconductivity were analyzed and attributed to oxygen stoichiometry. Results showed a strong relationship between paraconductivity and substrate type and the amount of insulator or gold in the films.

The carbon allotrope C60 or Buckminsterfullerene exhibits superconductivity at high temperatures, photoconductivity and other important biological properties. Experiments were conducted to investigate the interaction between Buckminsterfullerene and a water surface using a model. The model was derived using Langevin equations. The rates of interactions in the air-water-C60 system were examined. The short escape time of a single C60 molecule was attributed to its low binding energy. The findings also showed that C60 does not display a stable liquid phase.

A simulation of the cooling process encountered during fabrication of epitaxial Pb1-xLaxTiO3(PLT,x=0.00-0.12) thin films prepared on MgO(001) single-crystal substrates was done using an x-ray high-temperature attachment. X-ray diffraction measurements were performed at various temperatures during wich a ferroelectric 90 degrees domain structure has been evolved. Lattice constants and the degree of c-axis orientation of the epitaxial PLT films were evaluated as a function of temperature below the deposition temperature (650 degrees C).

The folded half-wavelength resonators in hairpin-comb filters all have the same orientation, whereas the orientations of the resonators in conventional hairpin-filters alternates. Hairpin-comb filters are shown to have attractive properties for design of compact, narrow-band filters such as are often desired for high-temperature-superconductivity (HTS) and other applications. The results obtained from two- and four-resonator trial HTS-filter designs are discussed. The filters are seen to have very strong stopbands, and their computed and measured performance are found to be in very good agreement. Index Terms - Bandpass filters, microstrip filters, superconducting filters.

Parametric resonance in a superconducting micron-scale resonator is related to the kinetic inductance in superconductors. This new effect is produced by temperature oscillations and can be applied to high-sensitivity tunable filters with Ghz-based modulated laser beams. Temperature-based resonant frequency is conditioned by superconducting electron behavior, as periodic variations of temperature excites microstrip current.

CeO2 insulating film was utilized as a high temperature multilayer in the fabrication of a YBaCuO crossover. An adequate critical temperature of 87 L and critical current density of 1.0x10(super 5) A/cm2 were observed at the bottom YBaCuO bridges. Top bridges, however, exhibited a lower critical current density because the grain boundaries were developed at the bottom bridge's step edges.

Two types of YBa2Cu3O7-based superconducting flux focusing devices were developed to improve the low field magnetoresistance in Nd0.7Sr0.3MnO3 films. YBa2Cu3O7 was found to focus the magnetic flux it expels from its interior to the films' bridge in the superconducting state. Pulsed laser deposition was utilized in in situ depositing YBa2Cu3O7/Nd0.7Sr0.3MnO3 on (100) LaAlO3 substrates for the successful integration of high temperature superconductivity and magnetoresistive effect.

A study was conducted on the factors that influence the uniformity of thin filaments Bi-2223/Ag superconducting tapes. Non-uniformities were found to be caused by shear fracture, sausaging and tensile fracture in the oxide core. These defects were theoretically explained as a function of the stress-dependent mechanical properties of superconducting powders. Results demonstrate that uniformity is enhanced by small roller size and low reduction rates during flat rolling.

A study was conducted to determine the optimal growth conditions of single-domain Sr2RuO4 epitaxial films. Films with good crystallinity were successfully grown at substrate temperatures higher than 1000-degrees celsius at high pressures. Films were found to predominantly consist of the SrRuO3 phase at lower temperatures and higher pressures. Measurements of resistivity vs temperature reveal that the Sr2RuO4 films grown were metallic but not superconducting.

The powder-in-tube (PIT) and surface-coated conductor methods were utilized in fabricating Tl-1223 conductors. Short monofilament tapes and meter-long 37-filament tapes exhibited current densities of 20,000 A/cm2 and 12,000 A/cm2 at 77 K, respectively. A new method was also proposed for the development of PIT Tl-1223 conductors with grain alignment. The approach successfully fabricated conductors with critical currents of 18 A and a 19,000A/cm2 Jc.

Problems in the fabrication of long single domain bars with high critical current densities have been stemming the development of YBCO superconductors for current leads. An approach using such additives as CeO2 is proposed for the directional solidification of very long single domain self sustained vertical bars. Results demonstrate that current leads capable of carrying currents higher than 2500 A may be developed using the approach.

A study was conducted on the current connectivity in Bi-2223 silver sheathed tapes for power cable applications. Current connectivity analysis was performed through magnetic and transport measurements. The field dependence was found to be a useful characterization parameter but failed in differentiating various connectivity mechanisms in the silver-sheathed tapes.

A thermal co-evaporation system was used for continuous YBa2Cu3O7-delta film deposition on large areas. Individual metal fluxes were measured through an atomic absorption spectroscopy-based optical rate control system. Results reveal that in situ reloading of metal resources at long time is possible. The grown films also exhibited excellent superconducting properties as compared to films developed using a standard co-evaporation system.

Measurements were conducted on the field- and frequency dependent alternating current (AC) susceptibility in melt-textured YBaCuO at 77 K and under different field conditions. AC induction RMS values were measured up to 13 mT, and direct current induction values were found to be 0, 20, 40, 75 and 100 mT. Results suggest that high temperature superconductors' AC susceptibility is dependent on frequency as well as on DC and AC induction.

An off axis deposition geometry is proposed for the enhancement of pulsed laser deposited YBCO thin films' surface quality. Resulting films exhibited excellent superconducting and structural properties as well as a surface morphology free from particulates such as droplets. A 0.12-degree full-width half maximum ofthe rocking curve of (005) YBCO peak was also observed. The effects of deposition parameters on film quality were also analyzed.

A study was conducted on a Josephson-effect based Hilbert-transform spectral analysis employing high temperature grain boundary Josephson junctions developed on (110) NdGaO3 bicrystal substrates. The Hilber-transform method initially measured the Josephson radiation spectra at 60-800 GHz. However, the potential to achieve a submillimeter range spectral resolution as low as 0.1 cm-1 was successfully tested at liquid nitrogen temperature.

A study was conducted on the strong microwave Josephson radiation emitted by an array of high-temperature junctions on a MgO bicrystal substrate from centimeter- to millimeter wave ranges. A pair of superconducting loop shunted junctions were used to feed the direct current bias current to the parallel geometry junction array. A coherent output power of 13 pW without external external magnetic flux was observed in a five-junction array.

A high temperature superconducting quantum interference device (SQUID) microscope was proposed for imaging applications at atmospheric pressure and room temperature. The SQUID, which was cooled to liquid nitrogen temperature, was mounted on a sapphire rod's upper end below a silicon nitride vacuum window that is 3 micrometers thick. A SQUID-to-sample separation as low as 15 micrometers was achieved through the scheme.

An in-situ high-temperature superconducting edge-type Josephson junction preparation process is proposed for enhancing the electrical characteristics and uniformity of the junctions. A barrier layer and a counter electrode were also deposited in the base YBaCuO electrode edge. The resulting YBaCuO/PrBacuO/YBaCuO junctions exhibited larger critical current density and normal state conductance than those prepared ex-situ.

A ramp edge-geometry superconductor-normal-superconductor configuration was used to develop high-temperature superconducting Josephson junctions and direct current superconducting quantum interference devices. The electrodes used was Ag-doped YBa2Cu3O7-x and the barrier employed was PrBa2Cu3O7-x. The devices exhibited a voltage modulation of 37 micro V and a magnetic field noise of -2 pTHz(super 1/2) at 1 kHz.

A six-epitaxial layer-based process including a Co-doped-YBa2Cu3Ox normal-metal interlayer was used to develop high temperature superconductor-normalconductor-superconductor weak links in an edge geometry. The weak links feature SrTiO3 insulators and integrated YBa2Cu3Ox groundplanes. Junctions developed in a novel slot geometry were also proposed for junction and interconnect inductance reductions.

A multichannel heart scanner based on high-temperature superconductive quantum interference devices has been developed. The 7-channel system combines magnetometers to form planar gradiometers for noise suppression. The noise suppression, however, is restricted by 2% imbalance of the gradiometric configuration. The imbalance is attributed to transfer function inaccuracies and planar geometry deviations.

A stripline-resonator approach is proposed for the microwave measurement of the reactive and resistive components of hight-temperature Josephson junctions' impedance. The impedance is considered a function of frequency, temperature, input power and direct current applied magnetic field. The approach was validated through comparisons with a resistively shunted junction model.

Desegmentation techniques and Green's function were used to analyze dual-mode patch high temperature superconductor filters. Design curves involving filter parameters and physical dimensions of the square patch were identified and a precise circuit model has been developed for the filter design process. The method of moments was used to calculate coupling capacitances. Results were validated through simulations.

Twinned thin-film YBa2Cu3O7-delta-Ag-PbIn SQUIDs were analyzed using a 4.2 K scanning SQUID microscope. The microscope also measured the phase of the SQUIDs' order parameter for 13 different tunneling angles. Results show that the SQUIDs' order parameter is time-reversal symmetric to 5% in the a-b plane. The results also cancel certain time-reversal breaking order parameters .