Resonant Perturbation of Phonons in Cu(Au) Alloys Studied by Neutron Scattering

1971 ◽  
Vol 49 (18) ◽  
pp. 2291-2306 ◽  
Author(s):  
E. C. Svensson ◽  
W. A. Kamitakahara
Keyword(s):  
Single Crystals ◽  
Pure Copper ◽  
Large Mass ◽  
Mass Defect ◽  
Concentration Effects ◽  
Neutron Inelastic Scattering ◽  
Resonance Behavior ◽  
Scattering Measurements ◽  
Atomic Vibrations ◽  
Good Agreement

The atomic vibrations in single crystals of Cu(Au) alloys containing 1, 3, and 9 at.% Au have been studied by means of neutron inelastic scattering. Measurements have been carried out for the [00ζ]T and [ζζ0]T1 branches of all three alloys and also for the [00ζ]L branch of the 9% alloy. In general, the impurity-induced widths, Γ, and the shifts, Δ, from the corresponding frequencies for pure copper exhibit definite resonance behavior. The detailed behavior of Δ and Γ as functions of frequency is, however, generally not in good agreement with calculations based on a mass-defect theory valid only for low impurity concentration. From the observed behavior of Δ and Γ for different branches and impurity concentrations, we conclude that, although the large mass change is undoubtedly the most important factor, force-constant changes and concentration effects also play important roles in determining the details of the resonance behavior in Cu(Au) alloys.

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

Measurement of growth rates for single crystals and pressed tablets of CuSO4.5 H2O on a rotating disc

1989 ◽  
Vol 54 (11) ◽  
pp. 2951-2961 ◽  
Author(s):  
Miloslav Karel ◽  
Jaroslav Nývlt
Keyword(s):  
Growth Rate ◽  
Single Crystal ◽  
Single Crystals ◽  
Growth Rates ◽  
Diffusion Coefficients ◽  
Preferred Orientation ◽  
Rotating Disc ◽  
Dissolution Rates ◽  
Rates Of Growth ◽  
Good Agreement

Measured growth and dissolution rates of single crystals and tablets were used to calculate the overall linear rates of growth and dissolution of CuSO4.5 H2O crystals. The growth rate for the tablet is by 20% higher than that calculated for the single crystal. It has been concluded that this difference is due to a preferred orientation of crystal faces on the tablet surface. Calculated diffusion coefficients and thicknesses of the diffusion and hydrodynamic layers in the vicinity of the growing or dissolving crystal are in good agreement with published values.

PWA OF πN SCATTERING WITH FIXED-t DISPERSION RELATIONS

2005 ◽  
Vol 20 (08n09) ◽  
pp. 1810-1813
Author(s):  
PEKKO PIIROLA ◽  
M. E. SAINIO
Keyword(s):  
Data Base ◽  
Forward Direction ◽  
Dispersion Relations ◽  
Data Sets ◽  
Coupling Constant ◽  
Partial Waves ◽  
Scattering Measurements ◽  
Pion Nucleon ◽  
Good Agreement

The πN scattering measurements from last couple of decades are not in very good agreement with each other. In fact, using the different data sets one finds different values for the pion-nucleon coupling constant. An analysis with theoretical constraints is the only way to produce accurate partial waves. In this analysis, the fixed-t dispersion relations are used to ensure analyticity in the invariant amplitudes and to decrease the effects of inaccuracies in the data base. Pietarinen's expansion is the method used to enforce the dispersion constraints. The strength of the analyticity constraints is illustrated with C± amplitudes in the forward direction.

scholarly journals A novel copper precursor for electron beam induced deposition

2018 ◽  
Vol 9 ◽  
pp. 1220-1227 ◽  
Author(s):  
Caspar Haverkamp ◽  
George Sarau ◽  
Mikhail N Polyakov ◽  
Ivo Utke ◽  
Marcos V Puydinger dos Santos ◽  
...  
Keyword(s):  
Electron Beam ◽  
Optical Transmission ◽  
Pure Copper ◽  
Dielectric Behavior ◽  
Copper Oxidation ◽  
Transmission Electron ◽  
Sum Formula ◽  
Electron Beam Induced Deposition ◽  
High Degree ◽  
Good Agreement

A fluorine free copper precursor, Cu(tbaoac)2 with the chemical sum formula CuC16O6H26 is introduced for focused electron beam induced deposition (FEBID). FEBID with 15 keV and 7 nA results in deposits with an atomic composition of Cu:O:C of approximately 1:1:2. Transmission electron microscopy proved that pure copper nanocrystals with sizes of up to around 15 nm were dispersed inside the carbonaceous matrix. Raman investigations revealed a high degree of amorphization of the carbonaceous matrix and showed hints for partial copper oxidation taking place selectively on the surfaces of the deposits. Optical transmission/reflection measurements of deposited pads showed a dielectric behavior of the material in the optical spectral range. The general behavior of the permittivity could be described by applying the Maxwell–Garnett mixing model to amorphous carbon and copper. The dielectric function measured from deposited pads was used to simulate the optical response of tip arrays fabricated out of the same precursor and showed good agreement with measurements. This paves the way for future plasmonic applications with copper-FEBID.

New module for channeling radiation simulation in Geant4

2021 ◽  
Vol 16 (12) ◽  
pp. P12042
Author(s):  
A.A. Savchenko ◽  
W. Wagner
Keyword(s):  
Experimental Data ◽  
Single Crystals ◽  
Dipole Approximation ◽  
Relativistic Electrons ◽  
Planar Channeling ◽  
Classical Approach ◽  
Electrons And Positrons ◽  
Simulation Results ◽  
Channeling Radiation ◽  
Good Agreement

Abstract We present a new C++ module for simulation of channeling radiation to be implemented in Geant4 as a discrete physical process. The module allows simulation of channeling radiation from relativistic electrons and positrons with energies above 100 MeV for various types of single crystals. In this paper, we simulate planar channeling radiation applying the classical approach in the dipole approximation as a first attempt not yet considering other contributory processes. Simulation results are proved to be in a rather good agreement with experimental data.

Relationship Between Stress and Surface Roughness in Krypton Implanted MgO

1994 ◽  
Vol 356 ◽  
Author(s):  
Laurence Gea ◽  
Jean-Luc Loubet ◽  
Roger Brenier ◽  
Paul Thevenard
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscope ◽  
Single Crystals ◽  
Internal Stresses ◽  
Post Irradiation ◽  
Implantation Damage ◽  
Atomic Force ◽  
Microindentation Technique ◽  
Good Agreement

Abstract(001) MgO single crystals were implanted with 150 keV krypton ions (Kr+) at a fluence of 5.1016 ions.cm-2 . The implanted surface, observed with an Atomic Force Microscope (AFM) exhibits striking features that can be described as undulations with a wavelength of 0.5 [μm. We correlate these features to the decrease in density and the stresses induced by the implantation damage. As a matter of fact, a model of surface instabilities provides a relationship between the wavelength of the ondulations and internal stresses. Using this model, implantation stresses are calculated to 2.2 GPa. This is in good agreement with the value of 2 GPa obtained with the help of the microindentation technique and the literature data. Some effects of an ionizing post-irradiation on stress and surface roughness are described.

scholarly journals VMC proper motions of the Magellanic Bridge

2018 ◽  
Vol 14 (S344) ◽  
pp. 130-133 ◽  
Author(s):  
Thomas Schmidt ◽  
Maria-Rosa Cioni ◽  
Florian Niederhofer ◽  
Jonathan Diaz ◽  
Gal Matijevic
Keyword(s):  
Galaxy Evolution ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Large Mass ◽  
Proper Motions ◽  
Dynamical Simulation ◽  
Open Questions ◽  
The Hierarchical Structure ◽  
The Universe ◽  
Good Agreement

AbstractDwarf galaxies enable us to study early phases of galaxy evolution and are key to many open questions about the hierarchical structure of the Universe. The Large and Small Magellanic Cloud (LMC and SMC) are the most luminous dwarf galaxy satellites of the Milky Way (MW). They are most likely gravitationally bound to each other, and their last interaction occurred about 200 Myr ago. Also, they are in an early phase of minor merging with the MW and will impact the Galactic structure in the future because of their relatively large mass. However, there are still major uncertainties regarding their origin and their interactions with one another and with the Milky Way. We cross-correlated the VMC and Gaia DR2 data to select a sample of stars that likely belong to the Magellanic Bridge, a feature formed of gas and stars which is connecting the LMC and the SMC. We removed potential MW foregound stars using a combination of parallax and colour-magnitude criteria and calculated the proper motions of the Bridge member stars. Our analysis supports a motion of star towards the LMC, which was found to be in good agreement with a dynamical simulation, of the SMC being stripped by the LMC.

scholarly journals Neutron inelastic scattering measurements on Xe136 at En=0.7 to 100 MeV

2018 ◽  
Vol 98 (6) ◽  
Author(s):  
S. J. Daugherty ◽  
J. B. Albert ◽  
L. J. Kaufman ◽  
M. Devlin ◽  
N. Fotiades ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Neutron Inelastic Scattering ◽  
Scattering Measurements

scholarly journals Analysis of Electronic Properties from Magnetotransport Measurements on Ba(Fe1−xNix)2As2 Thin Films

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 630
Author(s):  
Ilya Shipulin ◽  
Stefan Richter ◽  
Aleena Anna Thomas ◽  
Kornelius Nielsch ◽  
Ruben Hühne ◽  
...  
Keyword(s):  
Single Crystals ◽  
Measurement Data ◽  
X Ray Diffraction ◽  
Crystalline Perfection ◽  
Ni Doping ◽  
Ginzburg Landau ◽  
Electronic Parameters ◽  
Electronic Heat ◽  
Good Agreement

We performed a detailed structural, magnetotransport, and superconducting analysis of thin epitaxial Ba(Fe1−xNix)2As2 films with Ni doping of x = 0.05 and 0.08, as prepared by pulsed laser deposition. X-ray diffraction studies demonstrate the high crystalline perfection of the films, which have a similar quality to single crystals. Furthermore, magnetotransport measurements of the films were performed in magnetic fields up to 9 T. The results we used to estimate the density of electronic states at the Fermi level, the coefficient of electronic heat capacity, and other electronic parameters for this compound, in their dependence on the dopant concentration within the framework of the Ginzburg–Landau–Abrikosov–Gorkov theory. The comparison of the determined parameters with measurement data on comparable Ba(Fe1−xNix)2As2 single crystals shows good agreement, which confirms the high quality of the obtained films.

Inelastic neutron scattering measurements on Nd2Fe14B single crystals

1991 ◽  
Vol 97 (1-3) ◽  
pp. 210-218 ◽  
Author(s):  
H.M. Mayer ◽  
M. Steiner ◽  
N. Stüβer ◽  
H. Weinfurter ◽  
K. Kakurai ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Single Crystals ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Scattering Measurements
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