On the thermally activated field evaporation of surface atoms

Impact of laser pulsing on the reconstruction in an atom probe tomography

“…The strong crystallography dependence of the specimen shape with increase in laser power could be explained by differences in the local field evaporation probability that relates to the local binding energy of the atoms, and thus to surface packing and coordination. Another effect that could play a very important role is the roll-up proposed by Waugh et al [39] and Wada [51] and experimentally observed by Schmidt and Ernst [52]. This refers to a tendency of atoms to migrate to positions of lower coordination, and thus the highest field, at the surface prior departing from the surface.…”

The Quantitative Analysis of Copper in Iron Based Alloys

“…These v a l u e s a r e c o n s i s t e n t with t h e observed p u l s e f r a c t i o n e f f e c t , namely t h e p r e f e r e n t i a l f i e l d evaporation of copper a t t h e a p p l i e d d.c. f i e l d , between pulses, i f t h e p u l s e f r a c t i o n i s too s m a l l . The observed temperature dependence of field evaporation can be explained qualitatively as a combination of two effects: i) the increased dependence of the evaporation rate, for each element, on the applied field as the temperature is decreased, and ii) the observed greater temperature dependence of the evaporation field for pure copper than for iron [12]. At higher temperatures therefore, a pulse fraction in excess of 25% would be needed to prevent the d.c. evaporation of copper.…”

Influence of experimental parameters on the composition of precipitates in metallic alloys

“…As demonstrated in the early work of Wada [29], the slope of the evaporation field vs. temperature differs for different species. Therefore, by progressively changing the base temperature, it is hoped that conditions on the evaporation field of the precipitates and the matrix could be found, which could greatly reduce the issues associated with local magnification, while maintaining analysis conditions that do not promote surface migration [30].…”