bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solid Solubility of Sb and Te Implanted GaAs Following Solid Phase Annealing
Authors: Johnson S.T. , Orrman-Rossiter K.G. , Williams J.S. 
Published: March 2011

ABSTRACTHigh dose antimony and tellurium implanted (100) GaAs wafers have been annealed in the solid phase under various time/temperature conditions using a conventional furnace, a rapid incoherent light source and a continuous wave CW Argon ion laser. The samples were capped with RF sputtered SiO2 prior to annealing and analysed using 2MeV He++ ion channeling to determine the solid solubility of the implanted ions. Results indicate that the Te is more soluble than Sb; highest solubilities measured were 6 × 1020cm−3 for Te and 1.3 × 1020cm−3 for Sb.
Raman Scattering and Luminescence Study of Rapid Annealing and Laser Irradiation Effects in Ion Implanted InP
Authors: Kirillov D. , Merz J.L. 
Published: March 2011

ABSTRACTRaman scattering and luminescence spectroscopic techniques were applied to the study of ion implantation of InP and its annealing by a lamp, oven, or laser beam. It was found that both characterization techniques give important information on surface layer transformation during implantation and annealing.
Raman Vibrational Study of Pulsed Laser Annealing of Implanted GaAs
Authors: Sapriel J. , Nissim Y.I. 
Published: March 2011

ABSTRACTThe lattice reconstruction produced by a pulsed laser irradiation in heavily damaged GaAs layers is studied. Spatially resolved Raman measurements are used to characterize the crystalline quality after the annealing cycle produced by a O-switched Ruby laser or by a picosecond pulsed Nd-YAG laser. The continuous evolution in the Raman spectra is usèd to follow the crystal recovery as a function of the irradiation parameters.
Growth of Nickel Silicides on Silicon by Short Duration Incoherent Light Exposure
Authors: Larsen A. Nylandsted , Chevallier J. , Sørensen G. 
Published: March 2011

ABSTRACTShort duration, incoherent light from a xenon lamp has been used to grow nickel silicides on silicon single crystals from evaporated nickel films. The formation of these silicides was studied by Rutherford Backscattering Spectrometry, channeling, sheet resistivity, and transmission electron microscopy as function of induced temperature (550– 775°C), exposure time (8– 25 sec), and silicon orientation (>111<, >110<, and >100<). Epitaxial NiSi2 films were formed for temperatures above ˜675°C whereas polycrystalline NiSi films were formed below this temperature.
Laser-Induced Synthesis of Thin GeSe2 Films
Authors: Antoniadis C. , Joliet M.C. , Andrew R. , Laude L.D. , Wautelet M. 
Published: March 2011

ABSTRACTThin films of GeSe2 are synthesized by laser irradiation of Ge-Se sandwiches, with 2Se:IGe atomic proportion. The synthesized free-standing films are demonstrated to have the monoclinic crystal structure of GeSe2. Moreover, they exhibit a preferential orientation, with the c-axis perpendicular to the plane of the film. Films synthesized on glass substrate are characterized by an indirect optical energy gap of 2.3 eV, in agreement with published data on GeSe2. The melting point of Ge is not attained in the case of films on glass substrate.
Laser-Solid Interactions: Localization of Momentum and of Energy
Authors: Van Vechten J. A. 
Published: March 2011

ABSTRACTMechanisms are discussed by which sufficient momentum and energy may be localized on individual atoms, ions or molecules to account for photoablation in different regimes. In order of increasing excitation intensity, these include the roles of: “recoilless emission” (as in Bragg scattering and the Mössbauer effect) during Auger recombination of a core exciton, particularly in the Knotek-Feibelman effect; the metastable binding of multiple holes earlier proposed by Feibelman, particularly in the data of Itoh and coworkers; the change in the equilibrium interatomic spacing concomitant with excitation of a Frenkel exciton (localized broken bond), particularly in the ablative photodecomposition reported by Srinivasan and co-workers; the interaction of virtual excitons with real excitons in a strongly polarized solid, e.g. one subject to laser annealing pulses; and the interaction of ions with surface plasmons, particularly in the laser sputtering data of Hanabusa et al. A connection is made to rapid annealing and to sub-threshold defect formation. Further support is noted for the bose condensation model of pulsed laser annealing.
Measurement of Ultrafast Melting and Regrowth Velocities in Pulsed Laser Heated Silicon
Authors: Bucksbaum Philip H. , Bokor Jeffrey 
Published: March 2011

ABSTRACTDirect measurements of the liquid/solid interface veiocity have been made during both melt-in and regrowth for puised (20 psec) ultraviolet lasei irradiation or crystailine silicon. The regrowth velocity was 25 m/sec, independent or laser fluence. Regrowtn velocities of 50 to 100 m/sec are expected from heat diffusion calculations which neglect undercooling, whereas the inclusion of an appropriate undercooling curve brings the calculation into good agreement with the data. Tne liquid films produced were up to 40 nm thick and were fully amorphized on resoliaificaion.
Oscillation in the Interlayer Coupling of Fe Films Across Cr Films Measured by Means of Light Scattering from Spin Waves and M(H)-Curves
Authors: Demokritov S. , Wolf J.A. , GrÜnberg P. , Zinn W. 
Published: March 2011

AbstractBy means of light scattering from spin waves and magnetooptical Kerr measurements we investigated the exchange interaction of two Fe films across a Cr film as a function of the Cr thickness dCr.Using good quality epitaxial samples with a special wedge geometry of the interspacer we observed up to four full periods of the long range oscillations of the exchange, including its ferromagnetic parts. At room temperatures the damping of the oscillations does not follow the d-2Crpendence predicted by zero-temperature RKKY-type theory.After a special e-beam treatment of the samples a short-range oscillation with a period around a lattice constant of Cr are discovered. The value of coupling in the maximum in this case shows considerable temperature dependence.The analysis of domain patterns and M(H) curves reveals the existence of a noncollinear interaction, which causes a configuration where the magnetizations of two Fe films are perpendicular to each other.
Magnetism and Magnetoresistance of Multilayers with Two Magnetic Components. I. Cu-Based Films
Authors: Yamamoto H. , Okuyama T. , Dohnomae H. , Shinjo T. 
Published: March 2011

AbstractMagnetoresistance (MR) properties were studied in Cu/Co/Cu/Ni80Fe20 system, and a large MR ratio was observed in weak external fields. In the course of field sweeping, these two magnetic components (Co and Ni(Fe)) are oriented antiparallel, because of the difference of coercive forces, and then the resistivity is greatly enhanced. The MR ratio was observed to be 10% at 300K, and 32% at 20K, respectively, in a multilayer \Cu(55Å)/ Co(25Å)/Cu(55Å)/Ni80Fe20(25Å)] ×15.
Magnetoresistance of Magnetically Uncoupled Multilayered Structures
Authors: Zhang Shufeng , Levy Peter M. 
Published: March 2011

AbstractThe magnetoresistive effect first observed in Fe/Cr and other antiferromagnetically coupled metallic multilayered structure, has also been observed, albeit somewhat attenuated, in structures where the magnetic layers are not coupled. We explain the magnetoresistive effect in these systems that are nominally uncoupled, and we provide a new interpretation for the magnetoresistance of Co/Cu, Fe/Cr and Co/Ru by considering these multilayered structures to consist of, not only ferro and antiferromagnetically aligned layers, but also mixtures of the two which have zero magnetization.
The Effect of Spin Dependent Scattering from Impurities on Giant Magnetoresistance and Thermal Conductivity in Fe/Cr Multilayers
Authors: Johnson B.L. , Camley R.E. 
Published: March 2011

AbstractRecent experiments have tested the assumption that a spin-dependent asymmetry in scattering is responsible for the giant magnetoresistance (GMR) in Fe/Cr multilayers by introducing additional impurities (with different spin-dependent scattering asymmetries) at the interfaces. This paper presents a theoretical calculation based on a Boltzmann transport equation approach which is appropriate for these new experiments. We find that when impurities (Mn, V) are introduced which have a spin-dependent scattering asymmetry similar to that of Cr in Fe the GMR is not substantially changed. When impurities (Al, Ir) with a spin-dependent scattering asymmetry opposite to that of Cr in Fe are introduced there is a rapid degredation of the GMR. Our results are compared with experiment and good agreement is found provided that the magnitude of the scattering asymmetry in Al is reduced somewhat from low-temperature published values. It is argued that thermal effects could indeed provide such a reduction. We also point out that the thermal conductivity should undergo changes with magnetic field in these structures, since the thermal conductivity also depends upon electron mobility.
Anisotropy Energies and Critical Behavior of Ultrathin Ni(111) Films Grown on Smooth and Rough W(110) (invited)
Authors: Li Yi , Baberschke K. 
Published: March 2011

Abstract6 to 80 Å thin Ni(111) films were prepared on smooth and rough W(110) substrates in UHV and characterized by LEED and Auger spectroscopies. The measurements of the magnetic properties were carried out in situ by ferromagnetic resonance at 9 GHz between 300 and 600 K. We found that the effective anisotropies, which consist of surface, crystal, and stress induced anisotropy, increase with decreasing film thickness and temperature. The roughness of the substrate results in the drastic decrease of the effective anisotropy. This is attributed to the change of the surface structure and the stress within the Ni films. Furthermore we found that the Curie temperature Tc and the critical exponent β of Ni films on the smooth and rough substrates show no change.
Magnetization and Curie Temperature of Ferromagnetic Ultrathin Films: The Influence of Magnetic Anisotropy and Dipolar Interactions (invited)
Authors: Bruno P. 
Published: March 2011

AbstractTheoretical investigations of the magnetization and Curie temperature of ferromagnetic ultrathin films in the presence of magnetic anisotropy and long-range dipolar interactions are presented. The Curie temperature of fcc (001) cobalt ultrathin films is calculated and compared with experimental results on Co/Cu (001) films. The influence of an external magnetic field, and the surface gradient of the magnetization are also discussed.
Morphology and Magnetic Phase Transitions of Monolayer-Range Fe Films on Au(001)
Authors: Liew Y.-F. , Wang G.-C. 
Published: March 2011

AbstractWe have studied the morphology and magnetic phase transitions of monolayer-range Fe films on a reconstructed Au(001) surface using the combination of High-Resolution Low-Energy Electron Diffraction (HRLEED) and Surface Magneto-Optic Kerr Effect (SMOKE) techniques. Through the measurement of energy dependent angular profiles of the specularly diffracted beam, we discovered a simple method to determine not only the interfacial spacings (Fe-Au and Fe-Fe) but also to detect the build up of the second layer. For a one-level (2-D) Fe films with coverage of ∼ 0.6 monolayer (ML) perpendicular magnetization was observed. For a 1 ML equivalent 3-D film both perpendicular and in-plane magnetization were observed. The magnetic phase transitions of these magnetic islands showed finite size broadening effect. The perpendicular saturation magnetization decreases with temperature above 100°C but never vanishes and the magnetization curve has no hysteresis loop above ∼ 120°C. The implication of superparamagnetism is discussed.
Magnetic and Structural Characteristics of Multi-layered Films Composed of Fe and Si Ultra-thin Layers
Authors: Kubota K. , Nagakubo M. , Naoe M. 
Published: March 2011

AbstractFe and Si layers were deposited alternately by using ion beam sputtering apparatus and the relationship between crystal structure and soft magnetic properties of these multi-layered films have been investigated in detail. The clear periodicity of multi-layered films was confirmed even at the thicknesses of Fe and Si layers δFe and δSi as small as 8.5 Å.The saturation magnetization 4πMs for all Fe layers decreased with decrease of δFe and δSi, and the coercivity Hc of these films took minimum of 1.0 Oe at δFe of 8.5 Å.Such a significant decrease of 4TEMs may be attributed to the formation of nonmagnetic regions at both side of each Fe layers. The thickness of these nonmagnetic regions may be estimated at approximately 1.5 Å from the measured value of 4flMs. This thickness seems to be very small because it is almost equal to that of one monolayer of bcc α-Fe. The low Hc of the films with δFe and δSi of 8.5 Å may be due to the formation of ultra-fine crystallites in Fe layer by insertion of amorphous Si layer and the direct magnetostatic interaction among Fe layers.
Magnetic Properties of Sputtered Ni/Al Multilayers
Authors: Tsang E. , Cates J. C. , Tan M. , Waknis A. , Alexander C. , Parker M.R. , Barnard J.A. 
Published: March 2011

AbstractMagnetic properties of sputtered Ni/Al multilayers have been investigated by vibrating sample magnetometry and ferromagnetic resonance. In these compositionally modulated films (CMFs) the Al ‘spacer’ layer thickness was fixed at 3.5 nm while the total Ni content of each film was held constant at 308 nm. The thickness of the individual Ni layers was varied from 4.8 to 154 nm. The CMFs showed a variety of magnetic characteristics which were dependent on the thickness of the Ni layers. CMFs with Ni layer thickness 30 nm and above showed clear evidence of perpendicular anisotropy. This anisotropy is characterized by low-remanence perpendicular hysteresis loops of the type commonly found in CoCr alloy films. As the Ni layer thickness diminishes the perpendicular anisotropy decreases and is eventually lost. Simultaneously, the CMFs show increasing in-plane remanence, rising to a peak squareness of greater than 0.5 at a Ni layer thickness of 11 nm. As the Ni thickness continues to decrease, the remanence again declines. At Ni thicknesses of a few nm the CMFs become quasi-superparamagnetic. These CMFs do not show a monotonic reduction in saturation magnetization, Ms, with decreasing Ni layer thickness. Instead, both Ms and the coercivity, Hc, pass through a maximum in the region of 40–80 nm Ni layer thickness. FMR measurements were also made on these films. A plot of the effective anisotropy field produces data of a similar form to the Ms versus Ni layer thickness plot, again with a clear maximum. The FMR data also reveals interesting resonances in the films exhibiting perpendicular anisotropy. The presence of satellite resonances adjacent to the principal resonance peaks seems to suggest, in structural terms, a two-phase system as the basis of the observed anisotropy.
MÖssbauer Measurements of Interfacial Magnetism of MBE Grown FE(100)/AG(100) Multilayers
Authors: Tang H. , Wieczorek M.D. , Keavney D.J. , Storm D.F. , Gutierrez C.J. , Qiu Z.Q. , Walker J.C. 
Published: March 2011

AbstractMultilayers of Fe(100)/Ag(100) were grown by MBE and analyzed with in situ RHEED and MÖssbauer spectroscopy. These films had a constant Ag layer thickness of 40 monolayers (ML) and varying Fe layer thicknesses of 3, 6, and 9 ML. Using MÖssbauer spectroscopy the presence of three Fe sites was inferred. From considerations of the hyperflne parameters and the relative intensities of the sextets, we assign one site to the bulk, and one to each interface: Fe on Ag and Ag on Fe. We believe that one explanation of this is differing tetragonal distortions at the two interfaces. Consequently, another series of films was grown in an attempt to distinguish these sites. These films were essentially identical to the 9 ML film above, but the Fe layers were composed of 56Fe, with a 2 ML 57Fe probe layer effused at the bulk and at each interface in turn. At this point 57Fe MÖssbauer spectroscopy was used to determine the hyperfine field and its temperature dependence for each of the three sites.
Preparation and Magnetism of CuO/A12O3 and CuO/MgO Artificial Superstructured Films
Authors: Sohma Mitsugu , Kawaguchi Kenji 
Published: March 2011

AbstractThree kinds of copper oxide (CuO) films, that is, CuO mono-layer films (MLFs), CuO/A12O3 artificial superstructured films (ASFs) and CuO/MgO ASFs were prepared by a reactive vapor deposition method. Magnetic susceptibility of the MLFs is almost constant against temperature and the Neel temperature (TN) is a little lower than that of bulk CuO. There is paramagnetic contribution proportional to the number of the interfaces for both kinds of ASFs. It is considered to be caused by imperfect -Cu-O-Cu- antiferromagnetic superexchange interactions located in the vicinity of interfaces.
Magnetic Anisotropy of Crystalline Defects
Authors: Clemens B.M. , White R.L. , Nix W.D. , Bain J.A. 
Published: March 2011

AbstractWe consider the anisotropies due to coherency strains and the inilioliogcliotis stratlus associated with misfit dislocations, both of which give rise to anisotropy through maguctostrictive coupling. Coherency strains can give rise to anl apparent surface anisotrnpy due to the decrease in coherency strain with the film thickness. This anisotropy is comparable in magnitude to that observed experimentally for Fe [110] epitaxial thiut films on W [110]. The strain field associated with misfit dislocations produces a. surface anisotropy which is also comparable in magnitude to experimentally observed anisotropies. Dislocatioms along the inplane [001] and [110] directions both produce the same preferred direction of maguctization orientation.
The Perpendicular Magnetic Anisotropy and Structure of Sputtered Ag/Co, Pd/Co, and AgPd/Co Multilayered Films
Authors: Yamaguchi Akira , Soe We-Hyo , Yamamoto Ryoichi , Kobayashi Masonobu 
Published: March 2011

AbstractThe structural and magnetic properties of sputtered Ag/Co, Pd/Co, and AgPd/Co multilayered films were investigated. When substrate temperature during deposition (Ts) was set at room temperature, the easy magnetization axis of the Pd/Co films with Co thickness less than 7Å was normal to the film plane and that of the Ag/Co films was parallel. AgPd/Co multilayered films showed a transition of the preferred direction of magnetic moment from lying in the film plane towards lying along the film normal when increasing the Pd concentration above 81 at%. Moreover, an anomalous reduction of the saturation magnetization was found. The perpendicular magnetic anisotropy of Pd/Co films with low Ts increased with decreasing the thickness of Co layer. However, the Pd/Co films with high Ts showed opposite tendency.
Spin Polarized Photoemission Studies of Surfaces and Thin Films
Authors: Johnson Peter D. , Brookes N.B. , Chang Y. 
Published: March 2011

AbstractSpin polarized photoemission is used to study the magnetic states associated with the clean iron (001) surface. These studies reveal evidence for a minority spin surface state in agreement with a first principles calculation. Studies of the same surface with silver and chromium epitaxial overlayers reveal evidence for interface states derived from this state found on the clean surface. In the case of the silver overlayer the binding energy of the new state is found to be dependent on the layer by layer thickness of the overlayer. With chromium overlayers the binding energy for the same interface state does not show the same thickness dependence. However a second interface state is observed immediately below the Fermi level. These changes in the interfacial electronic structure have implications for any modelling of magnetic coupling in multilayers dependent on the magnetic properties of the interface.
Epitaxial Rare-Earth Superlattices and Films
Authors: Salamon M.B. , Beach R.S. , Borchers J.A. , Erwin R. W. , Flynn C.P. , Matheny A. , Rhyne J.J. , Tsui F. 
Published: March 2011

AbstractEpitaxial growth of rare-earth superlattices is demonstrated to have opened important new areas of research on magnetic materials. The propagation magnetic order through non-magnetic elements, including its range and anisotropy, has been studied. The importance of magnetostriction in determining the phase diagram is demonstrated by the changes induced by epitaxial clamping. The crystallinity of epitaxial superlattices provides the opportunity to study interfacial magnetism by conventional x-ray and neutron scattering methods.
Zeolite Crystal Layers Coupled To Piezoelectric Sensors: Molecular Recognition Demces
Authors: Yan Yongan , Bein Thomas 
Published: March 2011

ABSTRACTMicroporous zeolite crystals were successfully coupled onto the gold electrodes of quartz crystal microbalances (QCM). A self-assembled monolayer of thiol-alkoxysilane coupling agent on the gold surface was used as the Interfacial layer to promote adhesion of the zeolite crystals to the QCM. The resulting, densely packed single layers of zeolite crystals were stable to at least 625 K. Transient sorption behavior of organic vapor pulses, dynamic vapor sorption isotherms and nitrogen sorption isotherms at liquid nitrogen temperature were examined to characterize the zeolite-coated QCMs. Depending on the type of zeolite coating, the resonance frequency response to vapor pulses could be increased up to 500-fold compared to the bare QCM. The regular micropores (0.3–0.8 nm) of the QCM-attached zeolite crystals were found to control molecular access into the extensive intrazeolite volume. Selectivity of the frequency response in excess of 100:1 toward molecules of different size and/or shape could be demonstrated. An additional recognition mechanism based upon intrazeolite diffusion rates was also established.
Formation And Characterization Of Sulfide Clusters In Molecular Sieve Zeolite Materials
Authors: Winterer Markus , Iton Lennox E. , Johnson Stanley A. , Maroni Victor A. 
Published: March 2011

ABSTRACTThe incorporation of molybdenum into the faujasite pore system via reaction of MoCl5 with H-Y zeolite results in dealumination of the zeolite framework and formation of MoO3 species. These species are readily sulfided by H2S, but MoS2 clusters are not produced. A sulfur-bridged dimeric molybdenum cluster, of proposed composition HO-Mo-(S)3-Mo-OH, is formed, which can strongly chemisorb CO. Sulfidation of niobium in this manner is not readily accomplished.
Directing Effect Of Fluoride In The Synthesis Of Molecular Sieves With New Characteristics And Of The First Twenty-Membered Ring Microporous Solid
Authors: Kessler Henri 
Published: March 2011

ABSTRACTThe directing effect of fluoride anions in the synthesis of molecular sieves seems to be related to the strength of its interaction with the framework. For example, whereas F is bridging 2 Al atoms of a four-membered ring in AlPO4-5 containing tetrapropylammonium fluoride and in an new triclinic morpholine-containing chabazite-like AlPO4, it is found in double four-rings in three other phases which were synthesized recently. Firstly in the tetragonal all-silica AST-type octadecasil (space group I4/m, a = 9.194(2)Å c = 13.396(4)Å) which was obtained in the presence of quinuclidine and HF. Secondly in two novel cubic microporous gallophosphates which are formed selectively in the presence of hydrofluoric acid. One has the structure type LTA (space group Fm3c, a = 24.0354(1)Å) and crystallizes with di-n-propylamine as a template, and the other shows a novel structure type (space group Fm3c, a = 51.84Å) with a 3-dimensional 20-membered ring channel system. This is the largest membered ring ever reported for a synthetic material.