, Volume 47, Issue 13, pp 5086-5096
Date: 22 Mar 2012

Dislocation structure at a \( \{ {\overline{1} 2\overline{1} 0} \}/ {\langle} 10\overline{1} 0 {\rangle} \) low-angle tilt grain boundary in LiNbO3

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Abstract

LiNbO3 is a ferroelectric material with a rhombohedral R3c structure at room temperature. A LiNbO3 bicrystal with a \( \{ {\overline{1} 2\overline{1} 0} \}/ {\langle}10\overline{1} 0{\rangle}\) 1° low-angle tilt grain boundary was successfully fabricated by diffusion bonding. The resultant boundary was then investigated using high-resolution TEM. The boundary composed a periodic array of dislocations with \( b = { 1}/ 3{\langle} \overline{1} 2\overline{1} 0{\rangle} \) . They dissociated into two partial dislocations by climb. A crystallographic consideration suggests that the Burgers vectors of the partial dislocations should be \( 1/ 3{\langle}01\overline{1} 0{\rangle} \) and \( 1/ 3{\langle}\overline{1} 100{\rangle} \) , and a stacking fault on \( \{ {\overline{1} 2\overline{1} 0} \} \) is formed between the two partial dislocations. From the separation distance of a partial dislocation pair, a stacking fault energy on \( \{ {\overline{1} 2\overline{1} 0} \} \) was estimated to be 0.25 J/m2 on the basis of isotropic elasticity theory.