ALTERNATE FIELD EVAPORATION AND KINK RELAXATION ON (001) AND (112) SURFACES OF TUNGSTEN NANOTIPS

2008 ◽  
Vol 07 (01) ◽  
pp. 37-41
Author(s):  
N. WANDERKA ◽  
I. M. MIKHAILOVSKIJ ◽  
V. A. KSENOFONTOV ◽  
T. I. MAZILOVA ◽  
E. V. SADANOV ◽  
...  
Keyword(s):  
Geometric Method ◽  
Fine Scale ◽  
Field Evaporation ◽  
Field Ion Microscopy ◽  
Scale Field ◽  
Atomic Relaxation ◽  
Kink Site ◽  
Ion Microscopy

Fine-scale field evaporation of stepped (001) and (112) surfaces of tungsten nanotips was studied by field ion microscopy. It was shown that some atoms at kinks and steps are anomalously stable against field evaporation. This effect is responsible for the observed alternate field evaporation near the kink and step sites. The phenomenon of alternate field evaporation could be used to determine an atomic relaxation at kinks on nanotip surface. Using the geometric method of analysis of field ion images, the normal to surface differential displacements of the kink-site atoms were estimated.

On the Shape of Field-Ion Emitters

1976 ◽  
Vol 34 ◽  
pp. 520-521
Author(s):  
H.C. Eaton ◽  
B.N. Ranganathan ◽  
T.W. Burwinkle ◽  
R. J. Bayuzick ◽  
J.J. Hren
Keyword(s):  
Grain Boundary ◽  
Spherical Shape ◽  
Theoretical Strength ◽  
Evaporation Process ◽  
Field Evaporation ◽  
Geometric Information ◽  
Field Ion Microscopy ◽  
Considerable Error ◽  
True Shape ◽  
Ion Microscopy

The shape of the emitter is of cardinal importance to field-ion microscopy. First, the field evaporation process itself is closely related to the initial tip shape. Secondly, the imaging stress, which is near the theoretical strength of the material and intrinsic to the imaging process, cannot be characterized without knowledge of the emitter shape. Finally, the problem of obtaining quantitative geometric information from the micrograph cannot be solved without knowing the shape. Previously published grain-boundary topographies were obtained employing an assumption of a spherical shape (1). The present investigation shows that the true shape deviates as much as 100 Å from sphericity and boundary reconstructions contain considerable error as a result.Our present procedures for obtaining tip shape may be summarized as follows. An empirical projection, D=f(θ), is obtained by digitizing the positions of poles on a field-ion micrograph.

scholarly journals High Fidelity Reconstruction of Experimental Field Ion Microscopy Data by Atomic Relaxation Simulations

2017 ◽  
Vol 23 (S1) ◽  
pp. 642-643 ◽  
Author(s):  
Shyam Katnagallu ◽  
Ali Nematollahi ◽  
Michal Dagan ◽  
Michael Moody ◽  
Blazej Grabowski ◽  
...  
Keyword(s):  
High Fidelity ◽  
Field Ion Microscopy ◽  
Experimental Field ◽  
Atomic Relaxation ◽  
Ion Microscopy ◽  
Microscopy Data

scholarly journals Automated Atom-By-Atom Three-Dimensional (3D) Reconstruction of Field Ion Microscopy Data

2017 ◽  
Vol 23 (2) ◽  
pp. 255-268 ◽  
Author(s):  
Michal Dagan ◽  
Baptiste Gault ◽  
George D. W. Smith ◽  
Paul A. J. Bagot ◽  
Michael P. Moody
Keyword(s):  
Three Dimensional ◽  
Reconstruction Algorithm ◽  
Automated Analysis ◽  
Atom Probe ◽  
Crystal Defects ◽  
Steel Matrix ◽  
Field Evaporation ◽  
Field Ion Microscopy ◽  
Ion Microscopy ◽  
Microscopy Data

AbstractAn automated procedure has been developed for the reconstruction of field ion microscopy (FIM) data that maintains its atomistic nature. FIM characterizes individual atoms on the specimen’s surface, evolving subject to field evaporation, in a series of two-dimensional (2D) images. Its unique spatial resolution enables direct imaging of crystal defects as small as single vacancies. To fully exploit FIM’s potential, automated analysis tools are required. The reconstruction algorithm developed here relies on minimal assumptions and is sensitive to atomic coordinates of all imaged atoms. It tracks the atoms across a sequence of images, allocating each to its respective crystallographic plane. The result is a highly accurate 3D lattice-resolved reconstruction. The procedure is applied to over 2000 tungsten atoms, including ion-implanted planes. The approach is further adapted to analyze carbides in a steel matrix, demonstrating its applicability to a range of materials. A vast amount of information is collected during the experiment that can underpin advanced analyses such as automated detection of “out of sequence” events, subangstrom surface displacements and defects effects on neighboring atoms. These analyses have the potential to reveal new insights into the field evaporation process and contribute to improving accuracy and scope of 3D FIM and atom probe characterization.

The annealing of radiation damage in tungsten investigated by field-ion microscopy

1969 ◽  
Vol 312 (1508) ◽  
pp. 51-63 ◽  
Keyword(s):  
Stage Iii ◽  
Simultaneous Increase ◽  
Field Evaporation ◽  
Field Ion Microscopy ◽  
Interstitial Defect ◽  
Interstitial Defects ◽  
Evaporation Technique ◽  
Ion Microscopy ◽  
Small Clusters ◽  
Field Ion Microscope

Annealed tungsten wire has been reactor-irradiated to a dose of 10 17 n. v. t. ( > 1 MeV), and specimens for field-ion microscopy prepared from the wire. Vacancies could be identified in certain regions of the field-ion microscope image, and the size and shape of small clusters of vacancies could be found by careful field-evaporation. Using the field evaporation technique the clustering of vacancies has been followed in specimens that were unirradiated, irradiated, and given certain post-irradiation heat treatments. The only interstitial defects seen arose from impurities. Specimens examined after being annealed in stage III ( ~ 400°C), showed fewer single vacancies, and there was a simultaneous increase in the number of small vacancy clusters. It is concluded that stage III annealing in tungsten may be associated with the migration of single vacancies to small clusters, rather than the migration of an interstitial defect.

Selective field evaporation in field-ion microscopy for ordered alloys

1999 ◽  
Vol 85 (7) ◽  
pp. 3488-3493 ◽  
Author(s):  
Xi-jin Ge ◽  
Nan-xian Chen ◽  
Wen-qing Zhang ◽  
Feng-wu Zhu
Keyword(s):  
Field Evaporation ◽  
Field Ion Microscopy ◽  
Ordered Alloys ◽  
Ion Microscopy
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