bluuebunny/crossref_metadata_2025_split huggingface dataset:
CW Laser Crystallization of Soi Thermal analysis of the most critical parameters
Authors: Hode J.M. , Joly J.P. , Jeuch P. 
Published: March 2011

ABSTRACTWe present an overview of the thermal modeling of CW laser induced crystallization of SOI. The dynamical case for a three-layer structure is derived. Effects of the phase change (increase in reflectivity, latent heat) are also treated. Analytical expressions are given and the models are compared to experiment.
Electron-Beam Recrystallization of Silicon Layers on Silicon Dioxide
Authors: Inoue Tomoyasu , Shibata Kenji , Kato Koichi , Yoshii Toshio , Higashinakagawa Iwao , Taniguchi Kenji , Kashiwagi Masahiro 
Published: March 2011

ABSTRACTRecent progress of SOI growth by electron beam recrystallization is described. Transient temperature profile on the recrystallizing sample surface was analyzed experimentally by direct observation with a thermovision, which is essential for the understanding of crystal growith mechanism. SOI growth was performed by a spot beam annealing and a pseudo-line shaped beam annealing. The line shaped electron beam has been proved to be useful for large area crystallization.Emphasis was placed on lateral seeded recrystallization of silicon layer evaporated in an ultra high vacuum. Silicon layers with the seed area grown epitaxially during the evaporation and above 1 μm thickness were successfully recrystallized, resulting in reproducible lateral epitaxiy. The pseudo-line shaped electron beam formed by very high frequency oscillation enabled dimensional enlargement of lateral epitaxial growth. crystalline properties were characterized by analyses of Rutherford backscattering and electron channeling pattern.
Preparation of GaAs Soi and its Laser Recrystallization
Authors: Xiqiang LI , Zhihao Chen , Chenglu Lin , Weiyuan Wang 
Published: March 2011

ABSTRACTGaAs SOI consisting of a sputtered GaAs film on a SiO2 −Si or sapphire substrate is irradiated by CW Ar+ laser beam with a view to investigating its recrystallization. Using AES, x-ray diffraction, TEM and ED, we have studied the compositions, crystal orientations and grain size of the laser-irradiated GaAs films. The possible application of GaAs SOI to devices is discussed on the basis of the experimental results.
Luminescence Spectroscopy on Highly Excited Si - Experimental Determination of the Plasma Drift Velocity
Authors: Laurich B. , Forchel A. 
Published: March 2011

ABSTRACTThe emission spectra of the electron-hole plasma created at the surface of a Si sample by intense laser pulses (65 ns or 400 ps) are investigated. It is shown that the plasma drift is necessary for a consistent interpretation of the luminescence line shape and the energetic position of the line. We determine average densities up to 2.1019 cm−3 for 300K and typical drift velocities up to 4.106 cm/s.
Amorphization of Aubi Alloys by Laser Quenching and Ion Irradiation
Authors: Wolthuis A. , Stritzker B. 
Published: March 2011

ABSTRACTCrystalline AulO0−xBixalloy films (200≤×≤90) could be transformed into an amorphous state by either+laser (20 ns pulse length, 248 nm) or ion bombardment (Ar ions, 300 keV) of these films, which were mounted onto a substrate kept at low temperatures ( <10K). Several metastable Phases could beobtained by annealing of the amorphous phase before the starting equilibrium phase mixture was formed. The different phases were characterized by their different superconducting and electrical properties.
Effects of Pulsed Electron Beam Irradiation on Al Single Crystal With Pb Overlayers
Authors: Battaglin G. , Carnera A. , Dona L.F. , Rose Dalle , Kulkarni V.N. , Mazzoldi P. , D'Anna E. , Leggieri G. , Luches A. 
Published: March 2011

ABSTRACTThe effects of pulsed electron beam irradiation (pulse width 50 ns FWHM, electron eneries from 15 to 30 keV and current density in the range of 100 to 2300 A/cm2 ) on Al-Pb systemsprepared by vacuum evaporation of Pb layers from 500 Å to 2000 Å in thickness over Al single crystals have been investigated by Rutherford backscattering (RBS) and scanning electron microscopy.The main effects consist in a Pb loss which shows definite features as a function of the incident beam current density and in a mixing of Pb into Al which is unambiguously detected by a selective chemical etching of Pb still unreacted after irradiation.These experimental results are discussed on the basis of some heat flow model calculations which use Monte-Carlo data for the electron depth dose function.
Reflectivity and Grazing Angle Diffraction of Polarized Neutrons
Authors: Ankner J.F. , Majkrzak C.F. , Neumann D.A. , Matheny A. , Flynn C.P. 
Published: March 2011

AbstractUsing polarized-neutron reflectivity, one can determine the layer-averaged magnetic structure of films and multilayers with exquisite precision. By employing the closely related phenomenon of grazing-angle diffraction, it is possible to obtain information about the in-plane structure in interfacial layers some tens of Ångstroms thick. We have used polarized-beam methods to study the Y/Gd interface using both reflectivity and grazingangle diffraction and discuss the status of these experiments.
Magnetic Domain Imaging of Epitaxial thin Films by Spin-Polarized Scanning Electron Microscopy
Authors: Allenspach R. , Stampanoni M. 
Published: March 2011

AbstractThe formation of magnetic domains in thin epitaxial Co/Au(111) films is investigated by spin-polarized scanning electron microscopy. Three-monolayer films are shown to decay into out-of-plane domains of micrometer size. The transition from out-of-plane to in-plane magnetization at a crossover thickness of 4.5 layers is followed by imaging the domains, and the transition is shown to occur as a continuous rotation of the magnetization. The domain size in field-free-grown perpendicular films depends linearly on film thickness. From high-resolution line scans across magnetization reversals we determine the resolution in magnetic imaging to be better than 40 nm.
Interlayer Magnetic Coupling in Transition-Metal Multilayered Structures
Authors: Levy Peter M. , Fry J.L. , Ethridge E.C. 
Published: March 2011

AbstractRecent experiments have confirmed the main features of the interlayer coupling we calculated for Fe/Cr multilayers. We discuss the origins of these features and present new results on the interlayer coupling for Fe/Mo(100) multilayered structures. We find they share many of the features seen in Fe/Cr structures; in particular the rapid oscillations of the coupling which are suppressed by the roughness of the interfaces in sputtered superlattices.
Giant Magnetoresistance and Oscillatory Interlayer Exchange Coupling in Copper Based Multilayers
Authors: Parkin S.S.P. 
Published: March 2011

AbstractGiant magnetoresistance values exceeding 65% at room temperature are reported in antiferromagnetically coupled Co/Cu multilayers grown on Fe buffer layers using magnetron sputter deposition. For such samples the saturation fields exceed 10 kOe. However by taking advantage of the rapid decrease of the Co interlayer magnetic exchange coupling with increasing Cu spacer layer thickness, large magnetoresistance values exceeding 35% can be obtained at room temperature for saturation fields of just a few hundred oersted.
Magnetism and Magnetoresistance of Multilayers with Two Magnetic Components. II. Au-Based Films
Authors: Okuyama T. , Dohnomae H. , Yamamoto H. , Shinjo T. 
Published: March 2011

AbstractMagnetoresistance(MR) properties of Au-based multilayers including two magnetic components, i.e.\Au/Co/Au/Ni(Fe)]xn, were investigated and compared with those of Cu-based films. The interlayer coupling between Co and Ni(Fe) through Au layer was found to be strongly antiferromagnetic if the thickness is less than 35Å. Antiparallel alignment of magnetizations caused by the difference in the coercive fields of Co and Ni(Fe) layers is realized when the Au layer thickness is larger than 50Å. Then, the resistance is enhanced by the spin-dependent scattering but the observed MR ratio is smaller than the case of Cu-based multilayers.
Magnetic and Transport Properties of Ion Beam Sputtered FE/CR Multilayers
Authors: Inomata K. , Okuno S.N. , Hashimoto S. , Yusu K. 
Published: March 2011

AbstractFe/Cr/Fe sandwiches and (Fe/Cr)n, multilayers were prepared by ion beam sputtering on MgO(100) substrates by changing acceleration voltages. Lower acceleration voltage was crucial to obtain multilayers with high quality interfaces.Single crystalline Fe/Cr/Fe sandwiches were prepared with ambient substrate temperature having a relation of Fe(100)<110>//MgO(100)<lO0>.On the substrates with elevated temperature above 150°C,however,polycrystalline films were grown.Magnetic coupling between Fe-layers through intervening Cr layers was investigated by FMR using 9.4GHz,in which three resonance lines were observed for single crystalline Fe/Cr/Fe sandwiches and (Fe/Cr)n multilayers with antiferromagnetic Fe-layer interactions,while a single resonance line was observed for the polycrystalline films.Magnetoresistance measured on (20AFe/12ACr)5 single crystalline multilayers showed anisotropy in saturation fields Hs which are about 2 times lower in the applied field parallel to Fe<100> than to Fe<l10>,which is consistent with the magnetization process for the films.It was found that the shapes of the magnetoresistance curve vs magnetic field differ for H//Fe<100> and H//Fe<110>.
Magnetism and Magnetoresistance of Fe/Cr Composite Multilayers
Authors: Araki Satoru , Narumiya Yoshikazu , Shinjo Teruya 
Published: March 2011

AbstractFe/Cr multilayers with composite layered structures were prepared onto MgO (100) and glass substrates by alternate deposition in ultrahigh vacuum. A multilayer with two thicknesses of Fe layers shows a larger MR change, 6.2 % at RT and 13.5 % at 77 K, than a simple type ones with the applied field upto 3 k0e. This Is due to the ferrimagnetically coupled Fe layers. For the multilayers of Cr-composite type, the MR ratio could be enhanced, 12.9 % at RT with the field of 2 T.
Thickness Dependence of the Ferromagnetism of Pd Films
Authors: Bouarab S. , Demangeat C. , Mokrani A. , Dreysse H. 
Published: March 2011

AbstractWe report the electronic structure of Pd(001) films with various thicknesses, within a self-consistent real-space description of the Hubbard Hamiltonian. We point out that the onset of ferromagnetism in Pd films is not a surface effect, but is directly related to the thickness of the slab: when the lattice parameter increases, films of two or three planes become ferromagnetic. Films with increasing thicknesses (from five layers to the bulk size) need a greater increase of the lattice parameter. An important supplementary lattice expansion is necessary to obtain a free-standing ferromagnetic monolayer. The surprising experimental results of Pd films on Ag or Fe substrate, are well described within this framework.
Epitaxial τMnAl/AlAs/GaAs Heterostructures with Perpendicular Magnetization
Authors: Sands T. , Harbison J.P. , Allen S.J. , Leadbeater M.L , Cheeks T.L , Brasil M.J.S.P. , Chang C.C. , Ramesh R. , Florez L.T. , Derosa F. , Keramidas V.G. 
Published: March 2011

AbstractEpitaxial films of ferromagnetic τMnAl with perpendicular magnetization have been grown on {100}AlAs/GaAs substrates by molecular beam epitaxy. A multistep growth procedure involving the formation of a template followed by codeposition and subsequent annealing yields thin epitaxial τMnA1 films that exhibit the extraordinary Hall effect with nearly ideal hysteretic characteristics.
Structure and Magnetism of NI/FE Multilayers.
Authors: Jennett Nigel M. , DINGLEY D.J. 
Published: March 2011

AbstractX-ray diffractometry at grazing incidence has been performed upon Nin/Fen multilayers with 6<2n<30mpl (n = no. of monolayers per nn layer, mpl), as a further test that the observed reduction in magnetisation (as n decreases) was not due to interfacial alloying. The results show that the interfaces are terraced to the extent that pinholes occur in the thinner layers. The layers became continuous for modulations 2n>10mpl. Each X-ray scan revealed a series of peaks which corresponded to integer monolayer differences in modulation periodicity. In contrast, interfacial alloying would have produced a broad single peak.M-H loops were performed on the samples for the range of temperatures 6<T<300K using a vibrating sample magnetometer with the field always applied in the plane of the sample. The sample coercivity was observed to vary with modulation wavelength such that at a modulation of 2n=16mpl it was about a factor of three greater than at either 2n=6mpl or 2n=30mpl. The coercivity peak occurs at a value of n equal to the critical layer thickness for the transformation of the Fe from FCC to BCC. High angle X-ray diffractometry shows an apparent change in planar spacing at the same modulation layer thickness (n=8mpl).The ratio of remnant magnetisation at low temperature to that at room temperature, RT, was greater than unity for all the samples measured. The ratio increased as the modulation period of the samples decreased. This is consistent with a modulation period dependence of the Curie temperature of the Ni/Fe multilayers.
MBE-Grown Epitaxial Co/Cr Superlattices
Authors: Vavra W. , Elagoz S. , Clarke Roy , Uher C. 
Published: March 2011

AbstractA series of epitaxial Co/Cr superlattices has been grown by molecular beam epitaxy. The Cr is in a metastable hcp phase as confirmed by transmission electron microscopy, selected area diffraction, and reflection high energy electron diffraction. The Cr layers are 10Å thick in all samples while the Co layers are varied from 12Å to 40Å. The diffusion between Co and Cr is studied by SQUID magnetometry and indicates step-like interfaces in the best samples. Interfacial sharpness has also been found to be unusually sensitive to Co deposition rates, and in contrast with other superlattice systems, we find that sharper interfaces enhance parallel anisotropy. Hall effect measurements of the saturation field are within 10% of SQUID values. Magnetoresistance at 4.2K is only 1/3% which we believe is a consequence of the high density of states at the Fermi level of hcp Cr.
The Enhanced Magnetization Observed in FE/mo Multilayers Deposited by Ion-Beam Sputtering
Authors: Wang Y. , Cui F.Z. , Li W.Z. , Fan Y.D. 
Published: March 2011

AbstractFe/Mo multilayers, with varied Fe single layer thickness, tF, and Mo single layer thickness, tMO, were deposited by using a focusing ion-beam sputtering technique. Their structural and magnetic properties were studied. The periodic modulated structure was observed for all samples. An enhancement of magnetization over the value of bulk Fe was noticed for some samples. The change of lattice spacing of Fe layers, as a result of compress stress in the film plane, was considered to be responsible for the increase of the magnetization for Fe/Mo multilayers.
Absorption of Radiation by Magnetic Superlattices
Authors: LePage J.G. , Camley R.E. 
Published: March 2011

AbstractWe calculate the absorption of infra-red radiation by a magnetic superlattice composed of alternating ferromagnetic films. Although the films are ferromagnetic, the interfacial interaction is antiferromagnetic (i.e. Fe/Gd or Co/Gd). As has been shown previously, such a system can exist in several distinct phases, and we calculate the power absorption for these different phases. The spin wave modes of the system were found and used to construct a Green's function via an eigenvector expansion. The incoming radiation was modeled as an oscillating magnetic field which was assumed to decay into the material. Given this driving field, the Green's function yields the response of the system. Our results indicate that a simple absorption measurement can be used to probe for surface and bulk magnetic phase transitions. Additionally, we can find the response of the system to a spatially uniform driving field and thus calculate the local susceptibility. We discuss the possibility of using such a susceptibility to find dipole-exchange modes in magnetic superlattices.
Perpendicular Magnetic Anisotropy of Pd/Co and Related Multilayers
Authors: Tsunashima S. , Nakamura K. , Takahashi H. , Fukatsu S. , Uchiyama S. 
Published: March 2011

AbstractMultilayer films consists of noble metal (Pd, Pt, Cu, Au, PdSi) and transition metal(Co, Ni, PdCo, PtCo, CoZr) layers were prepared by rf sputtering method on glass and/or MgO single crystal substrates. The perpendicular magnetic anisotropy was examined in relation to the magnetostriction, lattice misfits, crystallinity and crystal orientations. The results suggest that the perpendicular magnetic anisotropy in noble metal/PdCo alloy multilayers originates from the magnetoelastic energy of the PdCo layers under a stress due to the lattice misfits. In both Pd/Co and Pd/Ni multilayers, the anisotropy was found to depend on the crystal orientation, and the dependence is discussed from the view point of the magnetoelastic surface anisotropy.
Optical and Magneto-optical modeling of Ultra-thin Film Multilayers
Authors: McGahan William A , He Ping , Woollam John A 
Published: March 2011

AbstractA Method for calculation of the optical and magneto-optical response of multilayered structures in which the layers are atomically thick is presented. The method can be used to calculate the response of any flim which has arbitrary compositional varaiation in the direction normal to the film plane as well. Calculations are presented for Tb/Co compositionally modulated alloys.
Spin-Polarized Eels on Ultrathin FCC Co Layers on CU(100)
Authors: Kamper K.-P. , Abraham D.L. , Hopster H. 
Published: March 2011

AbstractThe magnetism and the electronic structure of fcc Co films epitaxially grown on Cu(100) was investigated by spin polarized electron energy loss spectroscopy. Films above 2 atomic layers thickness show ferromagnetic order above room temperature with the magnetization in the plane. An exchange splitting of 0.8 eV and a Stoner gap of 300 meV is found. Films thinner than 1.6 layers do not show remanent magnetization above 80 K. No evidence for enhanced moments in monolayer films is found.
Preparation Of Zirconium Diphosphonate-Phosphites With A Narrow Distribution Of Mesopores.
Authors: Alberti G. , Costantino U. , Vivani R. , Zappelli P. 
Published: March 2011

ABSTRACTThe presence of H3PO3 in the synthesis of zirconium diphosphonates in dimethylsulfoxide, other than the expected dilution of the pillars, which in turn gives rise to a certain degree of microporosity, may also induce the formation of a high percentag. of mesopores. E.g., compounds with high surface area(300–500 m2 /g) of which 60–70% is due to mesopores with diameters 20–40 Å and the remaining is due to micropores, were obtained. It was furthermore found that the distribution of the mesopores was fairly narrow. Compounds with micropores <3 Å and mesopores of 20–30 Å behave in practice as pure and narrow mesoporous solids;they are therefore of great interest as new molecular inorgano-organic sieves.
Photoreduction Of Methylviologen In The Interlayers Of Some Layered Titanates And Niobates
Authors: Nakato Teruyuki , Sugahara Yoshiyuki , kuroda Kazuyuki , Kato Chuzo 
Published: March 2011

ABSTRACTMethylviologen dication was intercalated to some layered semiconducting oxides, and the photoinduced electron transfer between the hosts and the guest was investigated. K4 Nb6O17, H2 Ti4O9, and HTiNbO5 were used as the layered oxides. The arrangements of methylviologen in the interlayers were deduced from the XRD results. UV irradiation of the intercalation compounds caused electron transfer from the hosts to the guest to form methylviologen radical cations. The radical cations were stable within a few minutes even in the presence of oxygen, and the decaying rates altered with the hosts. The difference was discussed on the basis of the structure of the intercalation compounds.
Intercalation Of Layered V2O5 Xerogel With Polymers
Authors: Kanatzidis M. G. , Wu C.-G. , Liu Y.-J. , DeGroot D. C. , Schindler J. L. , Marcy H. O. , Kannewurf C. R. 
Published: March 2011

ABSTRACTThe intercalation properties of the layered V2O5 xerogel towards conductive polymers are described. The systems intercalated with polyaniline show post-intercalative redox polymerization caused by ambient oxygen to give products with enhanced conductivity. For the first time the role of oxygen in this intercalation reaction has been unequivocally identified. We also report the synthesis and some properties of a new intercalation compound in which the guest species is poly(ethylene oxide), an insulating polymer.
Reduction of Cu2+ and Ni2+ In Zeolite Y Using Polyol Process: A New Approach In The Preparation Of Metal Supported Catalysts
Authors: Malla P. B. , Ravindranathan P. , Komarneni S. , Breval E. , Roy R. 
Published: March 2011

ABSTRACTZeolite NaY was exchanged with three levels of Cu2+ and Ni2+ ions which were subsequently reduced in ethylene glycol (polyol process) at 195° C. This process effectively reduced the transition metal ions to zerovalent forms and the degree of reduction was dependent on the amount of exchange and the location of transition metal ions. Polyol process was found to be more efficient in reducing these ions located in zeolite cages than commonly used molecular hydrogen. Comparison of reduction behavior of Cu2+ and Ni2+ ions indicated that better metal dispersion in NaY can be achieved for Ni2+ than Cu2+ by the polyol process.
Designing Zeolites As Novel Precursors To Electronic Ceramics
Authors: Corbin David R. , Parise John B. , Chowdhry Uma , Subramanian M. A. 
Published: March 2011

ABSTRACTThe decomposition of zeolites is a novel route for the synthesis of aluminosilicate-based ceramic materials. Zeolites offer a number of advantages as ceramic precursors which allow the formation of dense ceramics at lower temperatures than by conventional methods. Using various cation-exchanged zeolites, ceramics and ceramic composites containing anorthite (CaAl2Si2O8). mullite (Al6Si2O11) cordierite (Mg2Al4Si5O18). celsian (BaAl2Si2O8), and ß-spodumene (LiAlSi2O6) have been formed. Using Extended X-ray Absorption Fine Structure (EXAFS), we have studied the reconstructive transformation of strontium-exchanged zeolite A to Sr-anorthite and have shown that the primary coordination of strontium remains intact during conversion.
Preparation Of Ceramic Molecular Sieve Membranes
Authors: Geus E.R. , Schoonman J. , van Bekkum H. 
Published: March 2011

ABSTRACTThe preparation of a composite ceramic membrane consisting of large silicalite (MFI-type) crystals and a gas tight lead-boron silicate glaze is reported on. A one single crystal containing membrane model was prepared to establish the zeolite stability after each preparative step.
Atomic Force Microscopy Of Micron Size Silicalite Crystals
Authors: Rasch P. , Heckl W. M. , Deckman H. W. , Häberle W. 
Published: March 2011

ABSTRACTWe have imaged micron sized silicalite crystals with an atomic force microscope (AFM). High resolution images taken in the repulsive mode show a periodic pattern that locally has a symmetry and periodicity which can be mapped onto the expected image looking along the [010] direction. Extra spots, however, appear in the image in regions which should correspond to channels exposed at the surface. These extra spots are attributed to multiple tip effects which should not affect the ability to detect long range ordering. On a scale length of ˜ 3 – 5 unit cells, the ordering in images deviates from that expected for a perfect crystal. This may be due to imperfections in the ordering at crystal surfaces. One other important aspect of the surface crystallography is revealed in low resolution scans where definite steps / grooves in the exposed surface are seen. The results are discussed in terms of the potential of AFM as a probe of surface crystallography.