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Electron Microscopy of Irradiation‐Induced Defect Clusters in Magnesium Fluoride
Author(s) -
Barber D. J.
Publication year - 1966
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.19660160220
Subject(s) - crystallographic defect , irradiation , dislocation , electron microscope , materials science , electron beam processing , stacking fault , electron , magnesium , burgers vector , ionization , crystallography , molecular physics , condensed matter physics , optics , chemistry , ion , composite material , metallurgy , physics , nuclear physics , organic chemistry
The passage of electrons through thin crystals of magnesium fluoride produces point defects. These defects are mobile at temperatures normally attained under the electron beam, and they can give rise both to dislocation loops and to precipitate platelets. The aggregation of these radiation‐induced defects can be controlled by using a cooled specimen stage in the electron microscope. This allows the growth and characteristics of the defect clusters to be studied. Dislocation loops lie on {011} planes and they sometimes show stacking fault contrast; their Burgers vectors are 1/2 〈01 1 〉 and 〈01 1 〉. Prolonged irradiation can produce precipitates on and within the loops. Higher beam intensities produce precipitates directly. The nature of the loops and precipitates is discussed in relation to the production of point defects by ionization mechanisms and irradiation‐stimulated migration.