Single Crystal Fe Films Prepared by a Low Kinetic Energy Sputtering Method

1992 ◽  
Vol 7 (10) ◽  
pp. 839-843
Author(s):  
K. Ishii ◽  
H. Motai
Keyword(s):  
Kinetic Energy ◽  
Single Crystal

Threshold Fluence UV Laser Ablation of Single Crystal Bi2Sr2Ca1Cu2O8: Product Population and Kinetic Energy Distributions of Ejected Ionic Species

1990 ◽  
Vol 201 ◽  
Author(s):  
Lawrence Wiedeman ◽  
Hyun Sook Kim ◽  
Henry Helvajian
Keyword(s):  
Mass Spectrum ◽  
Kinetic Energy ◽  
Single Crystal ◽  
Mass Spectra ◽  
Laser Excitation ◽  
Population Distribution ◽  
Wavelength Dependence ◽  
Ionic Species ◽  
Uv Laser ◽  
Laser Fluences

AbstractWe have conducted an experiment which measures the product population and kinetic energy (KE) distributions from the UV laser induced decomposition of crystalline Bi2Sr2Ca1Cu2O8. We have measured these distributions at two laser wavelengths 248, 351. At a third wavelength (355 nm) we have measured the photoejected mass spectra from both a single crystal Bi2Sr2Ca1Cu2O8 sample and a polycrystalline Bi2Sr2Ca2Cu3O10 sample. For all the experiments, the laser fluence is maintained near the threshold for ion formation. The laser fluences are well below the level for instigating a laser induced above surface plasma. Our results show that the ejected products are not the consequence of a laser surface evaporation process. We measure a wavelength dependence in the ejected species population distribution and the ejected kinetic energy distribution (< KE > = 5 ± 1 eV.2eV FWHM) is indicative of an electronic excitation process. The measured ion mass spectra show atomic, diatomic (e.g. Sr2+), and oxide (e.g. SrO+, CaO+) species with lesser quantities of the complex oxides (e.g. S2O+). Distinctly absent from the mass spectra are the oxide compounds BiO+, CuO+, and the atomic species O+. Furthermore, the mass spectrum shows that at 248 nm laser excitation, the Bi+ species is the abundant photopro-duct. However, for both the 351 nm and 355 nm excitations, the Sr+ and SrO+ ions are measured as more abundant. Also, comparing the 355 nm laser excitation of the single and polycrystalline samples, there is very little difference in the photoejected species mass spectrum.

Kinetic Energy Density Induced by High Magnetic Fields in a Bi-2212 Single Crystal

2014 ◽  
Vol 28 (2) ◽  
pp. 411-414
Author(s):  
Moisés Leonardi de Almeida ◽  
Paulo Pureur ◽  
Fábio Teixeira Dias ◽  
Valdemar das Neves Vieira
Keyword(s):  
Energy Density ◽  
Kinetic Energy ◽  
Magnetic Fields ◽  
Single Crystal ◽  
High Magnetic Fields ◽  
Kinetic Energy Density

Reconstruction of the 3-D Atomic Structure of CoSi2 (111) by Photoelectron Holography

1993 ◽  
Vol 307 ◽  
Author(s):  
Y. Zhoul ◽  
X. Chen ◽  
J. C. Campuzano ◽  
G. Jennings ◽  
K. Gofron ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Synchrotron Radiation ◽  
Kinetic Energy ◽  
Single Crystal ◽  
Atomic Structure ◽  
Reconstruction Algorithm ◽  
Scattered Wave ◽  
Reference Wave ◽  
Core Electron ◽  
Computer Reconstruction

ABSTRACTWe report the use of photoelectron holography for the study of the atomic geometry of the (111) surface of single crystal CoSi2. We employ as a reference wave the Co 3p core electron emitted with a kinetic energy of 695 eV by absorption of synchrotron radiation. Remarkably sharp images of the nearest Si neighbors of the Co emitter were found using a computer reconstruction algorithm which compensates for the anisotropies of both reference and object waves. Comparison with other reconstruction schemes such as the Helmholtz-Kirchoff (HK) algorithm and the scattered-wave included Fourier transform (SWIFT), demonstrates the necessity of compensating for the reference-wave anisotropy.

Plasma and DLC Film Characteristics from Pulsed Laser Ablation Of Single Crystal Graphite and Amorphous Carbon: A Comparative Study Employing Electrostatic Probe Measurements

2000 ◽  
Vol 617 ◽  
Author(s):  
R. M. Mayo ◽  
J. W. Newman ◽  
A. Sharma ◽  
Y. Yamagata ◽  
J. Narayan
Keyword(s):  
Laser Ablation ◽  
Kinetic Energy ◽  
Single Crystal ◽  
Amorphous Carbon ◽  
Plasma Plume ◽  
Laser Energy ◽  
Heavy Particle ◽  
Complex Molecules ◽  
Ion Kinetic Energy ◽  
Lower Temperature

AbstractIn an ongoing effort to investigate plasma plume features yielding high quality DLC films, we have applied plasma plume diagnosis and film characterization to examine plume character distinction from KrF laser ablation of both amorphous carbon (a-C) and single crystal graphite (SCG) targets- The advancing plasma plume produced by these structurally different targets are observed to possess quantitatively similar total heavy particle inventory, ionized fraction, and electron thermal content, yet quite different ion kinetic energy, plume profile, C2 formation mechanism, and concentration of complex molecules. All data support the conclusion that the SCG target plasma plume is populated with heavier, more complex molecules than those in a-C which have been shown to be predominantly comprised of C and C+ under vacuum conditions with the addition of C2 at high fill pressure. Significantly smaller plume profile peaking factor, less energetic and slightly lower temperature plume conditions, laser energy (E1) dependent plume peaking, harder films produced at lower El strongly heterogeneous films, and lesser plume energy attenuation in high pressure background fill in SCG target plumes all support the conclusion of more massive plume species in SCG target plumes. Energy balance estimates indicate that ion kinetic energy dominates and that SCG target ablation liberates about twice the number of 12C atoms per unit El.

A Preparation of High Resolution Standards for Electron Microscopy. Part II

1971 ◽  
Vol 29 ◽  
pp. 160-161
Author(s):  
Akira Tanaka ◽  
David F. Harling
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Carbon Black ◽  
Single Crystal ◽  
Dark Field ◽  
Graphitized Carbon Black ◽  
Graphitized Carbon ◽  
Dark Field Imaging ◽  
Crystal Films ◽  
Micro Holes

In the previous paper, the author reported on a technique for preparing vapor-deposited single crystal films as high resolution standards for electron microscopy. The present paper is intended to describe the preparation of several high resolution standards for dark field microscopy and also to mention some results obtained from these studies. Three preparations were used initially: 1.) Graphitized carbon black, 2.) Epitaxially grown particles of different metals prepared by vapor deposition, and 3.) Particles grown epitaxially on the edge of micro-holes formed in a gold single crystal film.The authors successfully obtained dark field micrographs demonstrating the 3.4Å lattice spacing of graphitized carbon black and the Au single crystal (111) lattice of 2.35Å. The latter spacing is especially suitable for dark field imaging because of its preparation, as in 3.), above. After the deposited film of Au (001) orientation is prepared at 400°C the substrate temperature is raised, resulting in the formation of many square micro-holes caused by partial evaporation of the Au film.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

Dislocations, Ordering and Antiferromagnetic Domains in MnO

1970 ◽  
Vol 28 ◽  
pp. 522-523
Author(s):  
D. J. Barber ◽  
R. G. Evans
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
Optical Microscopy ◽  
Defect Chemistry ◽  
Magnetic Structures ◽  
Optically Transparent ◽  
Magnetic Features ◽  
Antiferromagnetic Domains

Manganese (II) oxide, MnO, in common with CoO, NiO and FeO, possesses the NaCl structure and shows antiferromagnetism below its Neel point, Tn∼ 122 K. However, the defect chemistry of the four oxides is different and the magnetic structures are not identical. The non-stoichiometry in MnO2 small (∼2%) and below the Tn the spins lie in (111) planes. Previous work reported observations of magnetic features in CoO and NiO. The aim of our work was to find explanations for certain resonance results on antiferromagnetic MnO.Foils of single crystal MnO were prepared from shaped discs by dissolution in a mixture of HCl and HNO3. Optical microscopy revealed that the etch-pitted foils contained cruciform-shaped precipitates, often thick and proud of the surface but red-colored when optically transparent (MnO is green). Electron diffraction and probe microanalysis indicated that the precipitates were Mn2O3, in contrast with recent findings of Co3O4 in CoO.

Electron Microscopy of Shock Loaded Polycrystalline Beryllium

1974 ◽  
Vol 32 ◽  
pp. 506-507 ◽  
Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens
Keyword(s):  
Electron Microscopy ◽  
Wave Propagation ◽  
Structural Change ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Shock Loading ◽  
Slip Systems ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

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