bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Improved Tool for Wedge-Polishing of Materials for Tem
Authors: Shaapur F. , Rimer J. 
Published: April 2011

AbstractA new and improved commercial version of a tool designed originally for angle-lapping to electron-transparency has been presented in this paper. The new tool commercially known as precision angle lapper (PALTM) was originally developed and introduced in 1995. The improvements incorporated in the PAL design were conceived and implemented mainly as a result of a systematic analysis of the original tool design, the shortcomings and complications encountered during the routine hands-on use of it, requirements for major auxiliary equipment in conjunction with application of the tool and, finally, the input from other users of the tool. The basis for each added and/or improved feature of the PAL has been individually discussed and the resulting advantages have been reviewed.
A New Tripod Polisher Method For Preparing Tem Specimens of Particles and Fibers
Authors: Arlderson Ron , Klepeis Stanley J. 
Published: April 2011

AbstractA tripod polisher method that extends the use of the tool to the preparation of difficult particulate and fiber specimens, sufficiently thin to permit direct TEM examination with minimal or no ion milling, is detailed. The specimen is surrounded with Si in order to take advantage of the colour changes displayed by thin Si to assess the thickness of the specimen during preparation.
Preparation of Cross-Section Tem Specimens of Semiconductors Containing Tungsten Interconnects Using Chemical Mechanical Polishing and Chemically Assisted ion Beam Milling, and Use of Afm to Evaluate the Success of These Procedures
Authors: Jamison Robert , Mardinly John , Susnitzky David , Duan Jian , Matos Carmen , Darknell Sharon 
Published: April 2011

AbstractTEM of semiconductors containing tungsten interconnects is hampered by the problem of tungsten being intrinsically opaque to the electron beam, and at the same time typically being much thicker than the rest of the specimen. This work describes a technique which can predictably and reproducibly thin tungsten to electron transparency using chemical mechanical polishing (CMP). Chemically-assisted ion beam etching (CAIBE) techniques were also investigated, but found to be of little benefit. The key to development and evaluation of these methods was the AFM.
The Use of a Cold Gas Plasma for the Final Processing of Contamination-Free Tem Specimens
Authors: Fischione P. E. , Ringnada J. , Feng Y. , Krekels T. , Hayies M , Colijn H. O. , Mills M J. , Wiezorek J. M 
Published: April 2011

AbstractThe issue of specimen contamination becomes more important at a rate proportional to the use of high-brightness electron source Transmission Electron Microscopes (TMM). The trend in the transmission electron microscopy of materials science specimens is to use higher-voltage microscopes incorporating field emission gun technology [1]. These FEG TEMs combine smaller electron probes with increased beam current, allowing high resolution specimen imaging and enhanced analytical data collection. This is of particular importance for semiconductor specimens which demand fine-probe microanalyis.
Preparation of Multilayered Materials in Cross-Section for in-Situ Tem Tensile Deformation Studies
Authors: Wall M. A. , Barbee T. W. 
Published: April 2011

AbstractThe success of in-situ transmission electron microscopy experimentation is often dictated by proper specimen preparation. We report here a novel technique permitting the production of crosssectioned tensile specimens of multilayered films for in-situ deformation studies. Of primary importance in the development of this technique is the production of an electron transparent microgauge section using focused ion beam technology. This micro-gauge section predetermines the position at which plastic deformation is initiated; crack nucleation, growth and failure are then subsequently observed.
Rocking-Angle Ion-Milling of Cross-Sectional Samples for Transmission Electron Microscopy of Multi-Layer Systems
Authors: Lee Jeong Soo , Kim Hyun Ha , Jeong Young Woo 
Published: April 2011

AbstractThe cross-sectional transmission electron microscopy (TEM) specimens of Pt/Ti/SiO2/Si, RuO2/SiO2/Si, W/TiN/SiO2/Si, (Pb,La)TiO3/Pt/MgO, Bi4Ti3O12/Lal-xCaxMnO3/MgO, and GaN/Al2O3 were successfully made by the rocking-angle ion-milling technique. The differential thinning problems could be effectively mitigated when the rocking-angle and the ion-beam incidence angle were optimized for each heterostructure. It was found that the sputtering yield ratio between the layer milled most quickly and the layer milled most slowly is one of the important factors which determine the optimum rocking-angle ion-milling condition. The atomic force microscopy study on the surface topography of the cross-sectional Pt/Ti/SiO2/Si TEM sample after ion-milling provided quantitative information about the effects of the rocking-angle variation. A parameter which is the ratio between the layer with a minimum electron transparency and the layer with a maximum electron transparency was suggested.
Eutectic Growth in Unidirectionally Solidified Fe-Cr-Ni Alloy
Authors: Okane Toshimitsu , Umeda Takateru 
Published: April 2011

ABSTRACTIn this report, transition of solidified phases for directionally solidified Fe-Cr-Ni alloys has been investigated in low growth rate range by using Bridgman type furnace. The ferrite-austenite eutectic growth has been confirmed like a plane front growth of ferrite single phase under low growth rate condition. The transition velocity between eutectic and ferrite cell growth has a good agreement with the result of calculation based on the phase selection criterion and the interface temperature calculation for ferrite, austenite and eutectic phases. These results show that the phase prediction by calculating interface temperature can be applied not only to competitive growth between single phases like peritectic systems, but also to eutectic systems. Furthermore, under the condition of eutectic coupled growth to be occurred in steady state, the changes of solidified phases and their morphologies in the initial transient are discussed.
Time-Dependent Nucleation in Partitioning Systems
Authors: Kelton K. F. , Narayan K. Lakshmi 
Published: April 2011

ABSTRACTNucleation in multi-component systems is poorly understood, particularly when the rates of long-range diffusion are comparable with the rates of attachment at the cluster interface. For illustration, measurements of the time-dependent nucleation rates in silicate and metallic glasses are discussed. A new model for nucleation in partitioning systems, which explains many of devitrification microstructural features in bulk metallic glasses, is presented.
Energetics of Stable and Metastable Low Temperature Iron Oxides and Oxyhydroxides
Authors: Laberty Ch. , Navrotsky A. 
Published: April 2011

ABSTRACTIron oxides and oxyhydroxides are widespread in nature. Understanding the thermodynamic properties of the transformation in the iron oxide/hydroxide system permits the characterization of numerous geochemical processes including weathering, soil chemistry, and diagenesis in continental and oceanic environments. The aim of this study is to measure the energetics of a series of metastable oxides and oxyhydroxides in order to determine the effects of polymorphism, of oxidation state and of hydration. High temperature solution calorimetry using sodium molybdate as a solvent and transposed temperature drop calorimetry at 979 K were used.Enthalpies of formation from the elements of the metastable iron oxides and oxyhydroxides were calculated from the measured values of the enthalpies of drop solution. The experiments allow an estimate of the enthalpy of formation from the elements of γFe2O3(−817.4 ± 1.2 kJ/mol for sample with tetragonal symmetry and −816.9 ± 1.2 kJ/mol for sample with cubic symmetry) and β-FeOOH (−561.3 ± 3.1 kJ/mol) which are currently unavailable in the literature.The stability of the structure depends mostly on the degree of hydration and on the average oxidation state of iron. It depends less strongly on the topology of the structure itself and of the tunnel anion.
Refinement of Size Distributions for Primary Crystallizations
Authors: Pineda E. , Pradell T. , Crespo D. , Clavaguera N. , ZHU J. , Clavaguera-Mora M. T. 
Published: April 2011

ABSTRACTThe microstructure developed in primary crystallizations is studied under realistic conditions. The primary crystallization of an amorphous alloy is modeled by considering the thermodynamics of a metastable phase transition and the kinetics of nucleation and crystal growth under isothermal annealing. A realistic growth rate, including an interface controlled growth at the beginning of the growth of each single grain and diffusion controlled growth process with soft impingement afterwards is considered. The reduction in the nucleation rate due to the compositional change in the remaining amorphous matrix is also taken into account. The microstructures developed during the transformation are obtained by using the Populational KJMA method, from the above thermodynamic and kinetic factors. Experimental data of transformed fraction, grain density, average grain size, grain size distribution and other related parameters obtained from annealed metallic glasses are modeled.
Coarsening of B2 Ordered Domains by Monte Carlo Simulations
Authors: Floc'h D. Le , Athènes M. , Bellon P. 
Published: April 2011

ABSTRACTWe present results concerning the study of growth and coarsening kinetics of ordered domains in a binary alloy exhibiting a B2 ordering at the stoichiometric composition. This study has been performed within the framework of an atomistic kinetic model based on vacancy migration using Monte Carlo simulations techniques. Contrary to the standard Lifshitz-Allen-Cahn law, it is observed that the coarsening exponent is a function of the annealing temperature, and also of parameters controlling the migration of the vacancy.
Production and Study of Ca/Sn(II) Metastable Fluoride Ion Conductors
Authors: Bell Michael F. , Dénès Georges , Zhu Zhimeng 
Published: April 2011

ABSTRACTPrecipitation reactions from aqueous solutions of calcium nitrate and tin(II) fluoride result in the formation of two metastable phases, depending on the reaction conditions. Crystalline CaSn2F6 and the microcrystalline Ca1-xSnxF2 solid solution are obtained, the latter crystallizing in the cubic fluorite (CaF2) type with total Ca/Sn disorder. Both phases are fluoride ion conductors. Electrical conductivity measurements versus temperature and bulk density measurements show that both phases are far from thermodynamic equilibrium at ambient conditions, and thus are metastable. Both decompose to a mixture of SnF2 and CaF2 at high temperature. In addition, CaSn2F6 is chemically unstable in an aqueous medium, in which it looses SnF2 to give the microcrystalline Ca1-xSnxF2 solid solution.
Ordered Omega Derivatives in (Zr3Al)-Nb Alloys
Authors: Tewari R. , Dey G. K. , Mukhopadhyay P. , Banerjee S. , Bendersky L. A. 
Published: April 2011

ABSTRACTVarious kinds of phase transformations, viz., spinodal decomposition, omega transformation, precipitation reactions and martensitic transformation can be induced in ternary (Zr3Al) -Nb alloys in conditions far removed from equilibrium. Transformation sequences in alloys containing 3% niobium are described and rationalized in terms of some basic tendencies such as phase separation and chemical ordering in the β (bcc) phase and displacive omega and β to α (hcp) transformations. Microstructures of rapidly solidified alloy showed a distribution of cuboidal (D88 phase) particles in the β matrix. The periodic arrangement of these particles along the <100>β directions was indicative of a spinodal transformation which preceded their formation. The β → D88 transformation could be accomplished by the superimposition of three processes, namely, chemical ordering, lattice collapse akin to ω transformation and vacancy ordering. During isothermal aging the D88 phase transformed into the B82 phase. The observed lattice correspondence and transformation morphology suggested that the D88 to B82 structural change involved the replacement of structural vacancies in the former by zirconium atoms without any reconstitution of the lattice. The evolution of the equilibrium Zr3Al (L12 structure) phase during prolonged aging were also studied.
Mechanisms of Layer Structure Formation in Peritectic Alloys
Authors: Mazumder P. , Trivedi R. , Karma A. 
Published: April 2011

ABSTRACTThe mechanisms of layer structure formation in the two phase region of peritectic systems are discussed. Under diffusive growth conditions, a banded structure is predicted within a narrow composition range in the hypoperitectic composition. Experimental studies show the formation of an oscillatory structure in the hyperperitectic region. It is shown that this structure is induced by convection in the melt, and it is a novel structure in which a large single tree-like structure of primary phase is surrounded by the peritectic phase. Basic ideas of convection that lead to this tree-like morphology are described.
Changes in Mass Density and Sound Velocity of Amorphous Pd80Si20by Low Temperature Ion Irradiation
Authors: Schumacher G. , Birtcher R. C. , Renush D. P. , Grimsditch M. , Rehn L. E. 
Published: April 2011

ABSTRACTChanges in transverse phonon sound velocity were measured during low temperature irradiation of amorphous Pd80Si20with 3.5 MeV krypton ions. The sound velocity decreases as a function of the ion fluence and shows a tendency to saturate at large fluences at a relative change of −4.7%. The changes in sound velocity were used to determine the changes in shear elastic constant and in Debye temperature both of which were in reasonable agreement with the value reported in the literature.
Diffusion-Governed-Asymmetric Growth of Amorphous Layer Under Solid-State Reaction in Ni-Zr Multilayers
Authors: Liu B. X. , Lai W. S. 
Published: April 2011

ABSTRACTA molecular-dynamics simulation with an n-body potential was performed to study solid-state amorphization in the Ni-Zr system upon annealing at medium temperatures ranging from 300 to 600 °C. The models for simulation were a Zr-Ni-Zr sandwich consisting of both hcp Zr and fcc Ni (001) atomic planes and a bilayer with a thin preset disordered interfacial layer, respectively, for revealing the detailed amorphization process and the growing kinetics of an amorphous layer upon solid-state reaction. Our simulation results demonstrated, for the first time, that the atomic process proceeded through first diffusion, then alloying and eventually amorphization. In other words, amorphization was controlled by a diffusion-limited reaction and the growth kinetics of the amorphous layer followed exactly a t1/2 law. Another interesting finding was that the growing speeds of the amorphous layer exhibited an asymmetric behavior, i.e. the amorphous layer extended faster towards Ni lattice than that directed to Zr side. Besides, it was also found that an initiation of amorphization upon annealing was dependent to the interfacial textures, i.e. amorphization could take place when the interfaces were composed of the more open atomic planes, whereas it was suppressed if the interfaces were constructed with the close-packed planes of both lattices.
Recrystallization of Si-, As- And BF2-Implanted, Bonded SOI
Authors: Tamura M. , Horiuchi M. 
Published: April 2011

ABSTRACTConventional and high-resolution cross-sectional TEM observations have been carried out on Si-, As- and BF2-implanted, bonded 100-nm-thick (001) SOI layers having polycrystalline Si (poly-Si) masks followed by annealing at 600°C. Amorphized SOI layers by these ion implantations are recrystallized through lateral solid-phase seeding epitaxy (L-SPE) by single crystal SOI under the poly-Si mask as a seed. The recrystallization of these SOI layers is completed in the order of BF2-, Si- and As-implanted layers by <110>-directed L-SPE, although the recrystallized layers have a high-density of {111}twins due to {111} facet formation at the growth front occurring during the first 30 s of annealing, independent of implanted ions. On the other hand, in the case of <100>-directed L-SPE, the growth of {110} faceted regions progresses after annealing for a few tens of minutes before folded {111} facets are formed, resulting in a good crystal quality region of 0.1∼0.2μm remaining, measured from the mask edge.
Thermal Drag of the Antiphase Domain Boundary Motion
Authors: Umantsev A. 
Published: April 2011

ABSTRACTAntiphase domain boundary is a region in materials where ordering of atoms changes from one structural variant to another. Influence of the internal energy excess on the dynamics of such boundary is considered in the framework of the Onsager theory of linear response. The internal energy transport entails a temperature hump in the transition region and causes a drag effect. An evolution equation that takes into account the finite thermal conductivity is derived. Experimental setup to reveal the thermal drag is suggested.
Structure, Morphology and Kinetics of the C49 to C54 Phase Transformation In Tisi2 Thin Films
Authors: Bocelli S , Marabelli F. , Iannuzzi M. , Miglio L. , Grimaldi M. G. , LaVia F. 
Published: April 2011

ABSTRACTA series of fine grained C49 thin films were prepared by depositing Ti films on heated amorphous as well as crystalline silicon substrates.Rapid thermal processing at temperatures between 700 and 775 °C was used to transform the metastable C49 phase into the stable C54. The evolution of the film structure and morphology during the transformation was investigated by sheet resistance, optical spectroscopy, diffuse reflectance and AFM measurements. One structural model which could account for our data is proposed according to crystallographic information present in the literature.
The Cubic to Hexagonal Phase Transition in Spray Deposited Tin-Doped Indium Oxide Films
Authors: Malik A. , Nunes R. , Martins R. 
Published: April 2011

ABSTRACTThis work's aim is to report for the first time the cubic to hexagonal phase transition in tindoped In2O3 films with a Sn/In atomic ratio of 0.03, fabricated at low temperature and normal pressure from alcoholic solution of InCl3 and SnCI4. The performed X-ray diffraction measurements show a difference between crystallographic symmetry of thin (100 nm) and thick (400 nm) films prepared in the same conditions: the structure of thick films can be related to high pressure In2O3 hexagonal system with a preferred orientation of c-axis parallel to the substrate surface, while thin films present a cubic symmetry with columnar (400) grain orientation. Phase transition nature is connected with non-axial tensile deformation of indium oxide grid due to insertion of chlorine ions in the position of two diagonally opposite oxygen vacancies in In2O3 network.
Pseudo-C11b Phase Formation of Titanium Disilicide During the C49 to C54 Transition
Authors: Smith Patrick L. , Ortega Richard , Brennan Bill 
Published: April 2011

ABSTRACTThe formation of TiSi2 thin films using the SALICIDE process on doped and undoped silicon substrates was studied. XRD TEM, AES, RBS and four probe Rs were used to characterize the material. Unit cell parameters and energetics were determined. Results confirm electrical and chemical signatures consistent with the known C49 conversion to C54. However, XRD indicated a structurally different intermediate phase occurs during the C49 to C54 transformation. Modeling was performed based on C11b structure (14/mmm) type, with the Ti and Si atoms arranged similarly to those in MoSi2. The unit cell was determined to be a = 4.428 Å, b = 4.779 Å, c = 9.078 Å with a Fmmm space group and total pseudo-potential plane wave calculations based on crystallographic simulations of −103.96 ev/Atom.
Point Defects And The B2 To Fcc Transformation In Milled FeRh
Authors: Peng Luke S.-J. , Collins Gary S. 
Published: April 2011

ABSTRACTMössbauer measurements were made on FeRh containing 52 atomic percent (at.%) Fe after mechanical milling for different times in a high-energy SPEX 8000 vibrator mill. Hyperfine fields are compared with fields for annealed ferromagnetic (F) samples having the B2 structure in the range 52–58 at.% Fe. For annealed F samples, hyperfine field shifts of -1.66 T and -1.12 T were detected at majority FeFC and minority FeRh probes due to FeRh antisite atoms in, respectively, the first and second atomic shells. Analysis of dipolar fields indicates that the magnetization lies along the <110> direction. The transformation from F B2 phase to a metastable paramagnetic fcc phase was observed that was half complete in 8 minutes. Analysis of spectra for the milled F B2 phase show that a second point defect was produced by milling that induces shifts of +6 T and +8.5 T, respectively, at majority and minority probes. Manyspectra fits were made under different defect models that led to the conclusion that milling produces point defects in the triple-defect configuration: 2 Fe-vacancies and 1 Fe-antisite atom. Defect concentrations were determined and show that the fractional concentration of vacancies on the Fe-sublattice increases linearly with milling time, reaching 3 at.% after 8 minutes, a very large value. The rate of transformation from B2 to fcc phase appears to be independent of the concentrations of point defects in the B2 phase, indicating that the transformation is purely stress-induced, as in a martensite transformation.
Microstructure Evolution in Al-Ag Alloys Under Severe Plastic Deformation
Authors: Haider F. , Voss H. 
Published: April 2011

ABSTRACTWe present results on the microstructure evolution in an A1Ag alloy after plastic deformation under fatigue at different temperatures, strain amplitudes and strain rates. Both the dislocation structure and the precipitate morphology and size distribution were analyzed. At low temperature, particle elongation and fragmentation was observed while at higher temperature an accelerated growth due to vacancy supersaturation was observed.
Superdendrites in Directional Solidification of Polymer-Solvent Mixtures
Authors: Ragnarsson Rolf , Utter Brian , Bodenschatz Eberhard 
Published: April 2011

ABSTRACTThe directional solidification of the transparent binary alloy succinonitrile-poly(ethylene oxide) was studied in an experiment in which solidification speeds of about 2 mm/sec could be reached without loss of the linear temperature gradient. The low diffusivity of the polymer solute allowed the study of the dynamics of rapid solidification using an optical microscope. For both normal and doublonic dendrites we observed a transition to large triangular “superdendrites” above a certain solidification speed and we report measurements of the primary and secondary spacing as a function of the pulling speed. Our measurements suggest that the observed triangular shape is due to a decoupling of primary and secondary growth at large undercooling.
Molecular Dynamics Calculations Of Melting and Fragmentation of Ar and Ag Clusters
Authors: Mazzone A. M. 
Published: April 2011

ABSTRACTMelting and fragmentation of Ar and Ag clusters, containing from 30 to 500 atoms, have been studied with an isothermal molecular dynamics simulation method using classical forces. The simulations describe either evaporative decay or collisional dissociation. In the first case it has been found that the increase of the temperature leads to a continuous transition from a softening of the bonds to fragmentation and,with a proper scaling of the temperature, the effect is similar in Ar and Ag. During the collisional decay a perceptible fragmentation yield is observed in Ar whereas in Ag the input energy is converted into translational energy and rigid motions.