UScholar Works
 
Filters: Department: "Physics" Journal Title: "Journal of Applied Physics" Collection: ir_uspace
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CreatorTitleDescriptionSubjectDate
1 Saam, Brian3He spin exchange cells for magnetic resonance imagingWe present a protocol for the consistent fabrication of glass cells to provide hyperpolarized (HP) 3He for pulmonary magnetic resonance imaging. The method for producing HP 3He is spin-exchange optical pumping. The valved cells must hold of order 1 atm.L of gas at up to 15 atm pressure. Because char...3He; Spin exchange cells; Hyperpolarized 3He; Pulmonary magnetic resonance imaging; Spin-exchange optical pumping; SEOP; Glass cells2002
2 Symko, Orest GeorgeAbsorption at radio frequencies in superconducting Y1Ba2Cu3OyThe large magnetic-field-dependent ac absorption in superconducting Y1Ba2Cu3Oy ceramics and powders decreases slowly with increasing frequency in the range 2-16 MHz. The magnetic-field-dependent ac absorption is observed below Tc in superconducting Y1Ba2Cu3Oy ceramics, powders and twinned crystals ...Copper-octahedral oxygen perovskites; Superconducting Y1Ba 2Cu3Oy; ac absorption1989
3 Williams, Clayton C.Atomic force microscope-force mapping and profiling on a sub 100-Å scaleA modified version of the atomic force microscope is introduced that enables a precise measurement of the force between a tip and a sample over a tip-sample distance range of 30-150Å. As an application, the force signal is used to maintain the tip-sample spacing constant, so that profiling can be ...Attractive force; Silicon wafer1987
4 Mattis, Daniel C.Band theory of ferromagnetism, antiferromagnetism, and spin wavesIntra-atomic exchange (Hund's rule mechanism) and Heisenberg nearest-neighbor exchange are examined for their role in the ferromagnetism of metals with degenerate bands. The equations of motion of spin waves valid near T=0°K are derived, and a number of branches are found. When the equations are ...Orbital degeneracy; Indirect exchange theory; Band theory1964
5 Symko, Orest GeorgeDiscrete spatial filtering with SQUID gradiometers in biomagnetismFirst-, second-, and third-order gradiometers used in detecting biomagnetic signals are analyzed as spatial niters. Their transfer functions independent of the source to be measured are presented and both the magnitude and phase characteristics of the transfer functions are analyzed. The distortion ...Spatial filtering; SQUID gradiometers; Fourier transform1986
6 Symko, Orest GeorgeEffect of RKKY interactions on the magnetization of dilute magnetic alloys with hcp hostsThe magnetization due to the presence of magnetic impurities dissolved dilutely in nonmagnetic H.C.P. host metals has been calculated assuming a fine structure splitting by an axially symmetric crystal field and an RKKY interaction between the impurities. To compute the RKKY contribution, the inte...RKKY interactions; Dilute magnetic alloys; HCP hosts; MgMn; ZnMn1981
7 Vardeny, Zeev ValentineElectrical and optical studies of gap states in self-assembled molecular aggregatesWe fabricated a variety of two-terminal devices using self-assembled monolayers (SAM) of solid-state mixtures comprised of molecular "wires" [1,4-methane-benzenedithiol (Me-BDT)] and molecular insulator "spacers" [1-pentanethiol], which were prepared at various molar concentrations ratio, r of wires...Gap states; Self-assembled molecular aggregates2007
8 Boehme, ChristophH loss mechanism during anneal of silicon nitride: chemical dissociationRemote plasma enhanced chemical vapor deposited silicon nitride (SixNyHz), produced at high ammonia to silane flow rates (ammonia rich) shows a reduction of hydrogen during rapid thermal anneal at temperatures that exceed the deposition temperature. This H release could be either due to a ‘‘slow...Anneal2000
9 Symko, Orest GeorgeMagnetic anisotropy of Zn-Cr alloys at very low temperaturesThe temperature dependent magnetization of Zn-Cr single crystals was measured from 2K down to 10 mK using a SQUID magnetometer. A large anisotropy is observed for the magnetization along the parallel and perpendicular axes of the crystal. For low concentrations impurity-impurity reactions do not do...Magnetic anisotropy; Zn-Cr alloys; Temperature dependent magnetization1978
10 Symko, Orest GeorgeMagnetic memory of oil paintingsThe color in oil paints is obtained sometimes from magnetic minerals. This fact implies that oil paintings could present an intrinsic magnetization. Magnetic imaging of an oil painting consists in the measurement of magnetic flux related to the magnetization of the painting. In this report results o...Magnetic memory; Oil paintings; Authentication2007
11 Symko, Orest GeorgeMagnetic shielding and relaxation characteristics of superconducting YBa2Cu3O7 tubesHigh-7c superconducting tubes have been developed for magnetic shielding of SQUIDs at 77 K. The characteristics of such tubes show that adequate shielding exists for magnetic fields up to a critical field determined by the current density of the tube. Relaxation phenomena with two different time de...YBa2Cu3O7 tubes; High-Tc; SQUID1989
12 Williams, Clayton C.Modeling and experimental investigation of cantilever dynamics in force detected single electron tunnelingThe dynamic response of a voltage biased oscillating cantilever probe is investigated through experimental and theoretical analysis as it approaches a dielectric surface. When the tip reaches the appropriate gap single electron tunneling events are detected between the metallic tip and the surface. ...Oscillating cantilever probe; Electron tunneling2004
13 Williams, Clayton C.Optical ranging by wavelength multiplexed interferometryA new optical technique is described for measurement of absolute distance. The approach is based upon a wavelength multiplexed heterodyne interferometer with FM demodulation. By temporally multiplexing discrete wavelengths in a heterodyne interferometer, a complete elimination of interferometric ra...Optical ranging; Distance1986
14 Vardeny, Zeev ValentineOptical studies of metallodielectric photonic crystals: bismuth and gallium infiltrated opalsWe have fabricated three-dimensional metallodielectric photonic crystals that consist of bismuth and gallium metals infiltrated into porous synthetic opals that have 300 nm diam silica balls. The specular reflectivity was measured in a broad spectral range from 0.3 to 25 mm using a variety of light ...Metallodielectric photonic crystals; Bismuth infiltrated opals; Gallium infiltrated opals; Bragg; Porous synthetic opals2004
15 Lupton, John MarkRecombination kinetics in wide gap electroluminescent conjugated polymers with on-chain emissive defectsWe analyze the experimental dependence of temporally and spectrally resolved electroluminescence (EL) from polyfluorene-based light-emitting diodes on electric field and temperature. The blue band in the EL spectrum is caused by emission from the polymer backbone, while the low-energy green emission...Recombination kinetics; On-chain emissive defects; Wide gap; Blue-emitting; Green-emitting; Excitons2003
16 Symko, Orest GeorgeSpin glass behavior of Cd1-xMnxTe below the nearest-neighbor percolation limitMagnetization measurements down to 10 mK of Cd, _ x Mn, Te for Mn concentrations 0.01<x<0.15 show spin glass behavior. Such behavior is attributed to short-range exchange and dipolar interactions. Both interactions are used to explain the concentration dependence of the spin freezing temperatures fo...Spin glass behavior; Cd1-xMnxTe1985
17 Vardeny, Zeev ValentineStudies of resonant and preresonant femtosecond degenerate four-wave mixing in unoriented conducting polymersDegenerate four-wave mixing with femtosecond time resolution is used to measure the magnitude and transient response of the third-order nonlinear optical susceptibility x(3) (ω;ω, -ω,ω) at 620 nm in nonoriented conducting polymers including polydiacetylene, polyacetylene, polyaniline, polydieth...Pi-conjugated polymers1991
18 Symko, Orest GeorgeSuperconducting microphone for photoacoustic spectroscopyA superconducting microphone has been developed for photoacoustic spectroscopy at low temperatures. The microphone consists of a thin mylar membrane coated with a film of lead whose motion is detected by SQUID magnetometer. For the simple set-up presented here, the limiting pressure sensitivity is ...Superconducting microphone; Photoacoustic spectroscopy; Low temperatures1982
19 Symko, Orest GeorgeTemperature dependence of the order parameter in a dilute AgMn spin glassThe magnetization of a dilute AgMn spin glass containing 150 ppm Mn has been measured over the temperature range from 20 mK to 2 K in an applied field of 0.9 Oe, using a SQUID magnetometer. A comparison of the measured magnetization with numerical calculations of the magnetization based on the Mean ...AgMn spin glass; Mean random field; MRF; Temperature dependence; Order parameter; RKKY interactions1982
20 Mishchenko, Eugene; Williams, Clayton C.Three-dimensional model of single-electron tunneling between a conductive probe and a localized electronic state in a dielectricMotivated by recent measurements of force detected single-electron tunneling, we present a three-dimensional model for the tunneling rate between a metallic tip and a localized electronic state in a dielectric surface. The tip is assumed to be semi-infinite, with electron wave functions approximated...Dielectric surface; Tunneling rate2007
21 Lupton, John MarkTime delayed electroluminescence overshoot in single layer polymer light-emitting diodes due to electrode luminescence quenchingWe investigate the transient response of single layer polymer light-emitting diodes (LEDs) based on poly[2-methoxy, 5-(2'ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV). An electroluminescence overshoot is observed between 1 and 2 μs after turning off the voltage pulse, depending on temperature...MEH-PPV; Delayed electroluminescence; Overshoot; Single layer; Electrode luminescence quenching; Transient responses2001
22 Vardeny, Zeev ValentineTransport studies of isolated molecular wires in self-assembled monolayer devicesWe have fabricated a variety of isolated molecule diodes based on self-assembled monolayers (SAM) of solid-state mixture (SSM) of molecular wires [1,4-methane benzene dithiol (Me-BDT)], and molecular insulator spacers [penthane 1-thiol (PT)] with different concentration ratios r of wires/spacers, wh...Transport studies; Molecular wires; Monolayer devices2005
23 Boehme, ChristophTriplet recombination at Pb centers and its implications for capture cross sectionsPulsed electrically detected magnetic resonance measurements are presented showing that Pb centers at the crystalline silicon (c-Sid) (111) to silicon dioxide sSiO2d interface can cause recombination of strongly coupled spin pairs in singlet and triplet configurations. The implication of these find...Silicon interfaces2005
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