bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effects of Sintering on the Microstructure and the Luminescent Characteristics of Polycrystalline ZnS
Authors: Adams R. Matthew , Mascher Peter , Kitai Adrian H. 
Published: April 2011

AbstractPositron annihilation spectroscopy and cathodoluminescence were employed to study changes in the microstructural and luminescent properties of pure and doped polycrystalline ZnS. All samples show evidence of defect clustering, when sintered at temperatures up to 400 °C, indicated by an increase in the average positron lifetime. The average lifetime of the undoped material is constant (at about 290 ps) from 300 to 700 °C, and then decreases beyond this temperature, due to the out diffusion of vacancy clusters. In comparison, the average lifetime for MnS doped material decreases beyond 600 °C. This decrease in the average lifetime is correlated with an increase in the luminescent intensity of the 585 nm Mn band, indicating that Mn compensation of zinc vacancies contributes to the decrease in the average lifetime. At sintering temperatures above 400 °C, the average lifetime of TbF3 doped material decreases by ∼3 ps / 100 °C, from a peak value of 285 ps, and then at 700 °C drops an additional 15 ps to 260 ps. At 650 °C a change from the distinct Tb spectrum to a broad band emission is observed It is believed that these effects can be linked to the incorporation of Tb3+ ions on Zn2+ lattice sites.
The Influence of Non-Stoichiometry on the Electrical Activation of n-Type Dopants in InP
Authors: Ridgway M. C. , Johnson C. M. , KringhØj P. 
Published: April 2011

AbstractThe influence of implantation-induced non-stoichiometry on the electrical activation and depth distribution of Group IV (Ge and Sn) and VI (Se and Te) elements in InP has been investigated with a variety of analytical techniques. Electrical measurements indicate that P co-implantation can increase the electrical activation of the Group IV elements through reductions in amphoteric behaviour and dopant-defect complexes for Ge and Sn, respectively. The relative influence of P co-implantation increases as the dopant ion dose increases. Though others have demonstrated that co-implantation increases the electrical activation of Group II elements, similar observations were not apparent for Group VI elements, the latter attributed to the lack of Group VI element interstitial character.
Improvement of Pin Photodiodes on the Soi Layer by Rapid Thermal Annealing
Authors: Fujii Yoshimaro , Usami Akira , Fujiyoshi Katsuhiro , Yoshida Hideaki , Ichimura Masaya 
Published: April 2011

AbstractElectrical properties of PIN photodiodes fabricated on the bonded silicon on insulator (SOI) wafers annealed at 900°C for 5 seconds were evaluated in order to investigate the effect of rapid thermal annealing (RTA) on SOI wafers. Traps in the SOI layers with different thicknesses (10,30,100 μm) were investigated using the deep level transient spectroscopy (DLTS) method. In the SOI layer with a thickness of 100 μm, a trap with deep energy level (about Ec-Et=0.55 eV) was observed and the concentration of the trap decreased from 5.0 × 1011 cm−3 to 1.5 × 1011 cm−3 by RTA. For PIN photodiodes on the 100 μm-thick SOI layer, the dark current decreased from 2 × 10−9 A to 6 × 10−10 A, and sensitivity uniformity for a 35 μmφ light spot and spectral responses were both improved by RTA. Lifetimes were obtained from open-circuit voltage (Voc) decay curves for 940 nm and 655 nm light, and they increased from 37 μs to 57 μs and from 47 μs to 62 μs, respectively, by RTA. For thinner SOI layers (thickness=10, 30 μm), PIN photodiodes have good uniformity and low dark current, and their characteristics were not changed by RTA.
Magnetic Phase Transitions in Epitaxial Fe/Cr Superlattices
Authors: Fullerton Eric E. , Riggs K. T. , Sowers C. H. , Berger A. , Bader S. D. 
Published: April 2011

ABSTRACTThe surface spin-flop and Néel transitions are examined in Fe/Cr superlattices. The surface spin-flop, originally predicted by Mills [Phys. Rev. Lett. 20, 18 (1968)], is observed in Fe/Cr(211) superlattices with antiferromagnetic interlayer coupling and uniaxial in-plane anisotropy. The Néel transition (TN) of Cr is observed in Fe/Cr(001) superlattices, for which the onset of antiferromagnetism is at a thickness tCr of 42Å. The bulk value of TN is approached asymptotically as tCr increases and is characterized by a three-dimensional shift exponent. These TN results are attributed to finite-size effects and spin-frustration near rough Fe-Cr interfaces.
Different Temperature Dependencies of Magnetic Interface and Volume Anisotropies in Gd / W(110)
Authors: Farle M. , Schulz B. , Aspelmeier A. , Andre G. , Baberschke K. 
Published: April 2011

ABSTRACTThe magnetic anisotropy of epitaxial Gd(0001) films on W(110) is determined as a function of temperature (150 to 350 K) and film thickness (9 to 30 monolayers) by in situ ferromagnetic resonance. It is found that the usual analysis in terms of a thickness independent part KV and a thickness dependent contribution 2KS/d must be performed at the same reduced temperature t = T/Tc(d). Kv shows qualitatively the same temperature dependence as the magnetocrystalline anisotropy of bulk Gd. It changes in sign near 0.7 Tc and does not vanish at Tc. KS on the other hand decreases linearly from 1.2 meV/atom at 0.6.Tc to zero at Tc. It appears that the intrinsic origin for Kv and KS is fundamentally different. The vanishing of KS at Tc indicates that two-ion anisotropy (spin-spin interaction) is dominating the interface anisotropy. The non- zero KV(T≥Tc) is likely due to a single ion magnetic anisotropy which is known for bulk Gd.
Perpendicular Resistance of Co/Cu Multilayers Prepared by Molecular Beam Epitaxy
Authors: List N.J. , Pratt W.P. , Howson M.A. , Xu J. , Walker M.J. , Hickey B.J. , Greig D. 
Published: April 2011

ABSTRACTResults are presented of the magnetoresistance of MBE-grown (111) Co/Cu multilayers measured with the current perpendicular to the plane of the layers (CPP). Although for measurements made with the more common geometry of current in the plane of the layers (CIP) there are large differences between the results on samples made by sputtering and those prepared by MBE, for these new CPP data the results on samples made by the two techniques are very much alike. For copper layers with thicknesses between 0.9nm to 6nm the magnetoresistance shows oscillations with copper thickness that were almost non-existent in the earlier CIP data. At the second peak the magnetoresistance in the CPP geometry is an order of magnitude greater than that in the CIP configuration. Although the interfaces in these samples have been shown to be very sharp, they appear to form a mosaic structure with the antiferromagnetic regions embedded in a ferromagnetic structure. It is argued that for CIP measurements the GMR is greatly reduced by these ferromagnetic correlations over lengthscales long compared to the electron mean free path. For CPP measurements, on the other hand, it is the spin diffusion length that is the determining factor with the mean free path no longer a key parameter and with values of the GMR virtually independent of the growth process.
Gmr Multihayer Patterned Structures
Authors: Melo L.V. , Rodrigues L.M. , Sousa A.T. , Freitas P.P. 
Published: April 2011

ABSTRACTCo-Cu-NiFe-Cu weakly coupled multilayers, were patterned into stripes with dimensions from 1×6μm2 to 2×20μm2. After proper biasing using a DC field created by an adjacent bias conductor, these structures show large linear field spans (±1500e), with MR values up to 6%. These can be used for current or position sensor applications. Sensor response to AC fields was studied up to 1Mhz, using the bias conductors as sources of the AC field. We find that the signal output is reduced above 10 to 100kHz. For comparison, sensors were also fabricated out Co-Cu AF-coupled multilayer (3×100μm2 structures) needed for field detection up to several kOe.
Giant Magnetoresistance and Oscillation in Epitaxial Fe/Cr(111) Multilayers
Authors: Chiang Wen-C. , Baxter David V. , Cheng Yang-Tse 
Published: April 2011

ABSTRACTWe report on the first studies of the giant magnetoresistance and oscillatory coupling in epitaxial Fe/Cr(111) multilayers. A series of samples were grown on hydrogen terminated Si(111) substrates at room temperature by UHV electron beam evaporation; with the thickness of Fe layer fixed at 30 Å, and the thickness of Cr layer varied from 10–47 Å. Giant magnetoresistance (GMR) is observed at 4.2 Å in these samples, with a maximum value of 13% for a Cr layer thickness of 13 Å. The associated oscillatory coupling is comparable to that reported in other crystallographic orientations in terms of both its period and phase.
Microstructure and Gmr in (111) Sputter-Deposited Co/Cu Multilayers
Authors: Pollard R.J. , Wilson M.J. , Grundy P.J. 
Published: April 2011

ABSTRACTThis paper presents the results of giant magnetoresistance (GMR), magnetic and microstructural investigations of sputter-deposited Co/Cu multilayers. The multilayers were designed to be at the second maximum of the oscillatory exchange coupling and were deposited onto a range of ion beam irradiated (111) Si substrates giving a transition from a random orientation to a highly oriented (111) texture. The randomly oriented multilayers exhibited mixed coupling and ∼20% GMR, which had components arising from irreversible and reversible magnetization changes, whereas the highly oriented (111) multilayers were almost completely ferromagnetically coupled and showed very little GMR.
Giant Magnetoresistance in Hybrid Magnetic Nanostructures Including Both Layers and Clusters
Authors: Schroeder P.A. , Holody P. , Loloee R. , Duvail J. L. , BarthÉlemy A. , Steren L.B. , Morel R. , Fert A. 
Published: April 2011

ABSTRACTEarly experiments to define oscillations in the CIP magnetoresistance (CIP-MR) of Ag/Co analogous to those for tcu < 5nm in Cu/Co were unsuccessful. The MR in this region was very small. Later experiments by Araki using thin (0.6nm ) Co layers produced much larger MRs and lead us to look at the MRs of similar samples more closely. We conclude that the large MR of such samples is associated with the discontinuous nature of the Co layers. The object of the present paper is to combine the high MR associated with the thin Co layers with the field dependence governed by the magnetization reversal in thick, and magnetically soft permalloy (Py) layers. We have measured the CIP-MR of sputtered samples of the [Co(O.4 nm)/Ag(tAg)/Py(tpy)/Ag(tAg)]×15 system with tAg ranging from 1.05 to 4nm and with tpy = 2 or 4nm. We obtain MRs at 4.2K as large as 35% in less than 100e with slopes as high as 5%/Oe. With CPP measurements slopes as high as 10%/Oe have been obtained. Squid magnetometer measurements indicate that, as the temperature increases, there is a crossover to superparamagnetic behaviour and a resulting gross deterioration of the MR slopes at room temperature. Efforts to increase the room temperature sensitivity are described. Detailed measurements of the CPP-MR of the [Co(0.4nm)/Ag(4nm)/Py(tpy)/Ag(4nm)]x20 series of multilayers are consistent with a two spin band model modified to take account of the granular nature of the Co.
Giant Magnetoresistance Behavior in Epitaxial Nd0.7Sr0.3MnO3−δ and La0.67Ba0.33MnO3−δ Thin Films
Authors: Xiong G.C. , Li Q. , Ju H.L. , Wu J. , Senapati L. , Greene R.L. , Venkatesan T. 
Published: April 2011

ABSTRACTEpitaxial Nd0.7Sr0.3MnO3-δ and La0.67Ba0.33MnO3-δ thin films with large magnetoresistance ratios have been prepared by pulsed laser deposition. Huge negative magnetoresistance ratios of -ΔR/RH > 1×106 % were obtained at 60 K and a magnetic field of 8 T in a Nd0.7Sr0.3MnO3-δ film. The influence of sample preparation conditions on the resistivity behavior of these films has been studied. Results suggest that oxygen stoichiometry and diffusion are important factors in causing the behavior observed in doped manganese oxide films.
Atom Specific Surface Magnetometry with Linear Magnetic Dichroism in Directional Photoemission
Authors: Rossi Giorgio , Sirotti Fausto , Panaccione Giancarlo 
Published: April 2011

ABSTRACTA practical atom specific surface magnetometry can be based on the measure of magnetic dichroism in the angular distribution of core photoelectrons using linearly polarized synchrotron radiation. The magnetic dichroism effect on the photoemission intensity of 3p core levels of the ferromagnetic transition elements is as large as 46% in the case of Fe(100). The most efficient scheme for measuring the magnetic dichroism in photoemission requires two mirror experiments in chiral geometry, i.e. only two times more experiments than standard core level photoemission for surface chemical analysis. We describe the dichroism magnetometry and show examples for Fe, Co, Ni and Cr surfaces and interfaces, including the measurement of the temperature dependence of the Fe(100) surface magnetization and of the effect of S-segregation on the surface magnetic moment of iron.
Soft X-Ray Optical Rotation as Element-Specific Magneto-Optical Probe
Authors: Kortright J.B. , Rice M. 
Published: April 2011

ABSTRACTContinuously tunable multilayer linear polarizers extend magneto-optical rotation techniques into the extreme ultraviolet and soft x-ray regions. Resonant magneto-optical rotation is large at the Fe L2,3 edges. Magneto-optical Kerr rotation can be either bulk or surface sensitive depending on incidence angle. A SMOKE hysteresis loop measured from the Fe in an Fe/Cr multilayer reveals high sensitivity and a complex magnetic response of Fe.
Ferromagnetic Behaviour in Nanoscale Cobalt Particles Dispersed by Zeolite Na-X.
Authors: Hussain I. , Gameson I. , Anderson P.A. , Edwards P. P. 
Published: April 2011

ABSTRACTThis investigation has looked at the preparation of nanoscale cobalt particles by a simple solid state reaction involving cobalt (II) nitrate and zeolite Na-X under vacuum conditions followed by reduction in an hydrogen atmosphere. Samples were characterised by powder x-ray diffraction and scanning/transmission electron microscopy (TEM). Magnetic measurements were performed on the samples below 300 K using a SQUID magnetometer.
Synthesis and Characterization of Organic/Inorganic Interpenetrating Polymer Networks
Authors: Bauer Barry J. , Jackson Catheryn L. , Liu Da-Wei 
Published: April 2011

ABSTRACTInterpenetrating polymer networks have been synthesized by performing sol-gel chemistry and conventional organic polymerizations in mixtures of the monomers. The organic polymers were acrylates, and the inorganic phase was SiO2 formed by hydrolysis of orthosilicates. Polymerizations were conducted at a variety of relative rates, and the chemistry was designed to allow different amounts of grafting between the components. The morphology was characterized by transmission electron microscopy and small angle neutron and x-ray scattering. Wide variations in morphology were observed depending on the polymerization conditions, ranging from grossly phase separated to dendritic to finely divided structures (at a 100Å size scale). The phases ranged from mixtures of the two components to relatively pure phases. The interface between the phases ranged from very narrow to relatively broad.
Removal of SiO2 From Si (100) by Remote H2/SiH4 Plasma Prior to Epitaxial Growth
Authors: Barnak J. P. , Ying H. , Chen Y. L. , Montgomery J. , Nemanich R. J. 
Published: April 2011

ABSTRACTThis study demonstrates the cleaning of Si(100) surfaces with a remote H2/SiH4 plasma. The surfaces were prepared with a chemical oxide the remains after an RCA clean. The plasma cleaning process was designed to remove contaminants such as C, F, and SiO2. The key to successful removal of the oxide is to have the plasma chemistry in a neutral deposition regime. The neutral deposition process regime is a balance between the deposition of Si by SiH4 and the etching of the deposited Si by atomic H. During the neutral deposition mode the SiO2 was removed without deposition of Si on the SiO2 surface. Once the SiO2 layer is removed, theunderlying Si surface is exposed to the H2/SiH4 plasma and a thin epitaxial film may be deposited. The final Si surface configuration after plasma cleaning is a 2×1 hydrogen terminated surface. The characterization of the interface and epitaxial film were investigated using Auger electron spectroscopy (AES) and transmission electron microscopy (TEM).
Deposition of Gan Films Using Seeded Supersonic Jets
Authors: Henry Lamb H. , Lai Ken K. , Torres Victor , Davis Robert F. 
Published: April 2011

AbstractGaN films were deposited on sapphire (0001) from triethylgallium (TEG) and NH3 seeded in separate He free jets. as the dissociative chemisorption of NH3 is expected to be rate-limiting in GaN growth, the NH3/He nozzle temperature was varied to control the incident kinetic energy of the NH3 molecules. Using an NH3/TEG flow ratio of 205 and an NH3/He nozzle temperature of 400°C, stoichiometric films were deposited at substrate temperatures ≥530°C. Scanning electron microscopy revealed that films deposited at 580°C are polycrystalline α-GaN with randomly oriented 0.5-μm grains. Films with a closely similar morphology are deposited by using an NH3/He nozzle temperature of 90°C. IN contrast, films deposited at 580°C using an NH3/He nozzle temperature of 510°C consist of whiskers (aspect ratio = c A. 4) which exhibit a-GaN (0001)/sapphire (0001) heteroepitaxy, as evidenced by X-ray diffraction and reflection high-energy electron diffraction.
Nitrogen Plasma Ion Implantation into Carbon Films Deposited by the Anodic Vacuum ARc
Authors: Husein Imad F. , Li Fan , Zhou Yuanzhong , Allen Ryne C. , Chan Chung 
Published: April 2011

AbstractAmorphous carbon films (a-C) deposited by the anodic vacuum arc on Si substrates were implanted with nitrogen using the Plasma Immersion Ion Implantation (PIII) technique to form carbon nitride films (CNX). Scanning Electron Microscopy (SEM) of the a-C films show a surface morphology with maximum grain size in the order of a few nanometers and the exclusion of macroparticles. INcreasing the nitrogen content of the CNX films increased the intensity of the X-ray Photoelecton Spectroscopy (XPS) C Is peak at 286.6 eV and formed a new peak at 285.6 eV which both can be associated with the carbon-nitrogen bond formation. Nanoindentaiton measurements showed that the hardness of the a-C films increased after implanting nitrogen into them. these CNX films exhibited a hardness of 19 GP A.
Dynamical Modeling of Laser ablation Processes
Authors: Leboeuf J. N. , Chen K. R. , Donato J. M. , Geohegan‡ D. B. , Liu C. L. , Puretzky A. A. , Wood ‡ R. F. 
Published: April 2011

AbstractSeveral physics and computational approaches have been developed to globally characterize phenomena important for film growth by pulsed laser deposition of materials. these include thermal models of laser-solid target interactions that initiate the vapor plume; plume ionization and heating through laser absorption beyond local thermodynamic equilibrium mechanisms; gas dynamic, hydrodynamic, and collisional descriptions of plume transport; and molecular dynamics models of the interaction of plume particles with the deposition substrate. the complexity of the phenomena involved in the laser ablation process is matched by the diversity of the modeling task, which combines materials science, atomic physics, and plasma physics.
Study of annealed Indium Tin Oxide Films Prepared by RF Reactive Magnetron Sputtering
Authors: Meng Li-Jian , Maçarico A. , Martins R. 
Published: April 2011

AbstractTin doped indium oxide (ITO) films were deposited on glass substrates by rf reactive magnetron sputtering using a metallic alloy target (In-Sn, 90-10). the post-deposition annealing has been done for ITO films in air and the effect of annealing temperature on the electrical, optical and structural properties of ITO films was studied. It has been found that the increase of the annealing temperature will improve the film electrical properties. the resistivity of as-deposited film is about 1.3 х 10-1 Ω*cm and decreases down to 6.9 х 10-3Ω*cm as the annealing temperature is increased up to 500 °C. IN addition, the annealing will also increase the film surface roughness which can improve the efficiency of amorphous silicon solar cells by increasing the amount of light trapping.
Surface and Interface Microstructure of Epitaxial Ferroelectric (Ba, Sr)Tio3 Thin Films
Authors: Alyoshin V. A. , Sviridov E. V. , Mukhortov Vi. M. , Zakharchenko I. N. , Dudkevich V. P. 
Published: April 2011

AbstractSurface and cross-section relief evolution of ferroelectric epitaxial (Ba,Sr)Ti03 films rf-sputtered on (001) MgO crystal cleavage surfaces versus the oxygen worKing gas pressure P and substrate temperature T were studied. Specific features of both three-dimensional and two-dimensional epitaxy mechanisms corresponding to various deposition conditions were revealed. Difference between low and high P-T-value 3D epitaxy was established. the deposition of films with mirror-smooth surfaces and perfect interfaces is shown to be possible.
Fatigue Crack Growth Behavior of Small Sn-Bi-Ag Solder Joints
Authors: Liu Tao , Korhonen M. A. , Ting S. , Kim D. , Li C.-Y. 
Published: April 2011

ABSTRACTReliability of solder interconnects is normally characterized by extrapolation of bulk solder reliability data, such as crack growth measurements of solder materials in the bulk form. In the present study, experimental evidence will be presented to show that crack growth, which is the most commonly observed failure mode in small solder joints strongly depends on the size and shape of the joint cross-section. Furthermore, the crack growth rate can be appropriately correlated to the size of the intense plastic yielding zone at the crack tip using a plastic decohesion argument.
Electronics Packaging Materials Research at NIST
Authors: Schen Michael A. , Davis G. T. , Mopsik F. I. , Wu W. L. , Wallace W. E. , Manning Jr. , Handwerker C. A. , Read D. T. 
Published: April 2011

ABSTRACTThe Materials Science and Engineering Laboratory at NIST has augmented its laboratory-based research in support of the U.S. commercial microelectronics industry by expanding its efforts in electronics packaging, interconnection and assembly (P/I/A) materials technologies. In conjunction with industry, university and other government agency partners, these new NIST efforts target materials technology issues that underlie the priorities contained within the various electronics industry technology roadmaps. A dominant aspect of the laboratory P/I/A program focuses on the in-situ metrology and data needs associated with the materials and complex material assemblies which comprise today's microelectronic components and circuits.
Ferroelectric Liquid Crystals for Nonlinear Optics: can we Really do It?
Authors: Walba David M. , Dyer Daniel J. , Cobben Peter L. , Sierra Teresa , Rego James A. , Liberko Charles A. , Shao Renfan , Clark Noel A. 
Published: April 2011

AbstractFerroelectric liquid crystals (FLCs) are true liquids with a thermodynamically stable polar structure. Furthermore, in some systems excellent polar stereocontrol has been demonstrated (> 80% of the molecular dipole oriented along the polar axis with infinite “thermal stability”). These properties make FLCs an interesting candidate for second order NLO applications. However, until now the orientation of organic functional arrays with “large β”, typified by the disperse red 1 (DRI) chromophore, has not been demonstrated.Herein we report the initial results of a study directed towards providing a solution to this problem. Specifically, a new FLC dopant wherein the DRI chromophore (p-nitro-p'-dialkyl-aminoazobenzene unit) is oriented along the polar axis in FLC mixtures up to 30% by weight is described. These results suggest that it will be possible to obtain FLCs with good stereocontrolled orientation of large β functional arrays. Given that hybrid VLSI silicon/FLC optical chips are under intense investigation as micro-displays, and manufacturing issues for this class of devices are being addressed in the display context, the materials presented here suggest VLSI/FLC chips may be useful as high speed electro-optic modulators as well.