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Proceedings Paper

Dislocations in LaBr3 crystals
Author(s): X. W. Zhou; F. P. Doty; Pin Yang
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Paper Abstract

Using a many-body embedded ion method potential for La-Br system, molecular dynamics simulations have been performed to study dislocations in the UCl3 type of LaBr3 crystal including identification of dislocation line energy, core structure, migration mechanism, and mobility. We found that dislocations with the < 0001 > Burgers vector can move under shear stresses, but they retain perfect dislocations during the motion rather than dissociated partials as commonly seen in metal systems. Unlike the < 0001 > edge dislocations whose mobility increases with temperature, the < 0001 > screw dislocations may become sessile at high temperatures due to thermally activated dissociation of the core. Dislocations with the <1120 > Burgers vector were found to be sessile due to non-planar dissociation at the core. Because the < 0001> dislocations can only slip on the {1 1 00 } prism plane and often only the edge dislocations are operative, the stresses created during any thermal mechanical processes cannot be effectively relieved by the plastic deformation mechanism. Considering that LaBr3 tend to cleave along the {1 1 00 } prism plane, the simulations shed some lights on why this material is so brittle and how large LaBr3 crystals tend to fracture during growth.

Paper Details

Date Published: 12 September 2009
PDF: 12 pages
Proc. SPIE 7450, Penetrating Radiation Systems and Applications X, 745005 (12 September 2009); doi: 10.1117/12.831055
Show Author Affiliations
X. W. Zhou, Sandia National Labs (United States)
F. P. Doty, Sandia National Labs (United States)
Pin Yang, Sandia National Labs (United States)


Published in SPIE Proceedings Vol. 7450:
Penetrating Radiation Systems and Applications X
F. Patrick Doty; H. Bradford Barber; Hans Roehrig; Richard C. Schirato, Editor(s)

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