Results

1 - 10 of 29
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Previous work on thermally induced arsenic deactivation in highly doped silicon has proven the generation bf vacancies and suggests the formation of arsenic-vacancy clusters as the deactivation mechanism. Using positron annihilation spectroscopy in the two-detector coincidence geometry, we are able ...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
A polycrystalline sample of Al63Cu25Fe12 has been studied as a function of thermal treatment by positron annihilation and X-ray diffraction techniques. Results suggest the presence of an icosahedral-to-rhombohedral microcrystalline phase transition near 300-degrees-C. Below this transition, a large ...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Samples of the stable Al75Pd15Fe10 decagonal quasicrystal have been studied both in the as-cast state and after annealing. Structural properties were investigated using X-ray diffraction and Fe-57 Mossbauer effect studies. X-ray patterns show that annealing improves the degree of order in the decago...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Amorphous Al-Y-Ni alloys, prepared by rapid solidification from the melt, have shown a unique combination of low density and high tensile strength. In the present work amorphous alloys of the composition Al87Y8Ni5-xFex (2 less-than-or-equal-to x less-than-or-equal-to 5) have been studied using room ...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Al-Cu-Fe alloys of several different stoichiometries have been prepared using a variety of sample preparation methods and have been studied using Fe-57 Mossbauer effect spectroscopy. Well ordered icosahedral, phason disordered icosahedral and rhombohedral crystalline phases were investigated. The re...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
A Doppler broadening positron annihilation technique which allows for the study of near surface defects in bulk samples is described. The method is capable of observing changes in the homogeneous bulk defect concentration in a sample acid is also able to characterize spatially localized near-surface...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Doppler-broadening positron-annihilation-spectroscopy experiment that utilizes an in situ Cu-64 source for the study of Cu and Cu-containing materials is described. This technique is particularly useful for the investigation of defect structure at elevated temperatures, and the present instrumentati...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Using a low-temperature stage X-ray diffractometer, we have investigated the temperature dependence of the lattice parameters of single crystal superconductors Bi2.2Sr1.8CaCu2Ox. The experimental results show that (i) the lattice constants increase linearly with increasing temperature above about 10...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
The positron beam technique is shown to be a sensitive indicator of the presence of arsenic within the grain boundaries of poly-silicon. Variable-energy positron beam and secondary-ion mass spectrometry studies have been performed on As+-implanted pre-amorphized Si samples as a function of dose and ...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]