Depth distribution of cavities in 20- and 500-KeV4 He+-irradiated nickel

Author(s):  
S. K. Das ◽  
G. Fenske ◽  
M. Kaminsky

Studies on depth distribution of damage and of cavities (voids and bubbles) in ion irradiated metals are of importance for an understanding of the mechanisms of radiation blistering and are of general interest to the field of radiation damage.The present paper describes transmission electron microscopy results on depth distribution of cavities and of dislocation damage in nickel irradiated at 500°C with 20- and 500-keV 4He+ ions. The results are compared with calculated projected range and damage energy distributions.High purity (99.995%) annealed polycrystalline nickel foils were irradiated at 500°C with either 20- or 500-keV 4He+ ions to total doses of 2.9 x 1016 and 1 x 1017 ions/cm2, respectively. Thin foils suitable for transmission electron microscopy were prepared from the irradiated samples by a transverse sectioning technique described elsewhere, which allows one to obtain depth distribution of damage and of bubbles from a single specimen.Figure 1 shows typical bright field transmission electron micrographs of the plated and irradiated regions of annealed polycrystalline nickel irradiated at 500°C with 500-keV 4He+ ions to a dose of 1 x 1017 ions/cm2.

Author(s):  
E. U. Lee ◽  
P. A. Garner ◽  
J. S. Owens

Evidence for ordering (1-6) of interstitial impurities (O and C) has been obtained in b.c.c. metals, such as niobium and tantalum. In this paper we report the atomic and microstructural changes in an oxygenated c.p.h. metal (alpha titanium) as observed by transmission electron microscopy and diffraction.Oxygen was introduced into zone-refined iodide titanium sheets of 0.005 in. thickness in an atmosphere of oxygen and argon at 650°C, homogenized at 800°C and furnace-cooled in argon. Subsequently, thin foils were prepared by electrolytic polishing and examined in a JEM-7 electron microscope, operated at 100 KV.


Author(s):  
W. D. Cooper ◽  
C. S. Hartley ◽  
J. J. Hren

Interpretation of electron microscope images of crystalline lattice defects can be greatly aided by computer simulation of theoretical contrast from continuum models of such defects in thin foils. Several computer programs exist at the present time, but none are sufficiently general to permit their use as an aid in the identification of the range of defect types encountered in electron microscopy. This paper presents progress in the development of a more general computer program for this purpose which eliminates a number of restrictions contained in other programs. In particular, the program permits a variety of foil geometries and defect types to be simulated.The conventional approximation of non-interacting columns is employed for evaluation of the two-beam dynamical scattering equations by a piecewise solution of the Howie-Whelan equations.


2007 ◽  
Vol 1026 ◽  
Author(s):  
Pascale Bayle-Guillemaud ◽  
Aurelien Masseboeuf ◽  
Fabien Cheynis ◽  
Jean-Christophe Toussaint ◽  
Olivier Fruchart ◽  
...  

AbstractThis paper presents investigations of magnetization configuration evolution during in-situ magnetic processes in materials exhibiting planar and perpendicular magnetic anisotropy. Transmission electron microscopy has been used to perform magnetic imaging. Fresnel contrasts in Lorentz Transmission Electron Microscopy (LTEM) and phase retrieval methods such as Transport of Intensity Equation (TIE) solving or electron holography have been implemented. These techniques are sensitive to magnetic induction perpendicular to the electron beam and can give access to a spatially resolved (resolution better than 10 nm) mapping of magnetic induction distribution and could be extended to dynamical studies during in-situ observation. Thin foils of FePd alloys with a strong perpendicular magnetic anisotropy (PMA) and self-assembled Fe dots are presented. Both are studied during magnetization processes exhibiting the capacities of in-situ magnetic imaging in a TEM.


2010 ◽  
Vol 16 (S2) ◽  
pp. 80-81 ◽  
Author(s):  
SD Findlay ◽  
N Shibata ◽  
H Sawada ◽  
E Okunishi ◽  
Y Kondo ◽  
...  

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.


2005 ◽  
Vol 899 ◽  
Author(s):  
Yoosuf Picard ◽  
Steven M. Yalisove

AbstractPre-thinned foils composed of amorphous silicon and polycrystalline cobalt were irradiated using femtosecond pulse-length lasers at fluences sufficient for ablation (material removal). The resultant ablated hole and surrounding vicinity was studied using transmission electron microscopy to determine modifications to the structure. Evidence of cobalt silicide formation was observed within a 3 micron radius of the laser hole edge by use of selected area electron diffraction (SAED). In addition, elongated grains of crystalline silicon was observed within 500 nm of the laser hole edge, indicating melting of the amorphous silicon and heat dissipation slow enough to allow recyrstallization. This initial work demonstrates the use of pre-designed nanostructured multilayer systems as a method for nanoscale profiling of heat dissipation following pulsed laser irradiation.


2010 ◽  
Vol 645-648 ◽  
pp. 713-716 ◽  
Author(s):  
Ming Hung Weng ◽  
Fabrizio Roccaforte ◽  
Filippo Giannazzo ◽  
Salvatore di Franco ◽  
Corrado Bongiorno ◽  
...  

This paper reports on the electrical activation and structural analysis of Al implanted 4H-SiC. The evolution of the implant damage during high temperature (1650 – 1700 °C) annealing results in the presence of extended defects and precipitates, whose density and depth distribution in the implanted sheet was accurately studied for two different ion fluences (1.31014 and 1.31015 cm-2) by transmission electron microscopy. Furthermore, the profiles of electrically active Al were determined by scanning capacitance microscopy. Only a limited electrical activation (10%) was measured for both fluences in the samples annealed without a capping layer. The use of a graphite capping layer to protect the surface during annealing showed a beneficial effect, yielding both a reduced surface roughness and an increased electrical activation (20% for the highest fluence and 30% for the lowest one) with respect to samples annealed without the capping layer.


1988 ◽  
Vol 3 (6) ◽  
pp. 1238-1246 ◽  
Author(s):  
J. K. N. Lindner ◽  
E. H. te Kaat

Six MeV high-dose Ni implantation into silicon has been applied to synthesize deep-buried metallic layers. These layers have been analyzed by optical reflectivity and spreading resistance depth profiling as well as transmission electron microscopy and cross-section transmission electron microscopy. Already in the as-implanted state, at target temperatures of 450 K and doses above 1017 Ni/cm2, epitaxial precipitates of NiSi2 are formed. They grow in type-A and type-B orientations. In addition to these polyhedral crystallites, thin NiSi2 platelets on {111} lattice planes exist. At a dose of 1.3 × 1018 Ni/cm2, a continuous but highly defective layer of epitaxial NiSi2 is formed by coalescence of mainly type-A precipitates at the maximum of the Ni profile. Investigations indicate that damage gettering of nickel atoms as well as the atomic density increase during implantation influence the depth distribution of implanted metal atoms. Moreover, a suppression of silicon amorphization by nickel is evident.


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