Threading dislocation generation in epitaxial „Ba,Sr...TiO3 films grown on „001... LaAlO3 by pulsed laser deposition

Epitaxial Ba0.6Sr0.4TiO3 films were grown onto ~001! LaAlO3 by pulsed-laser deposition, and the dislocation structures of the films were investigated using transmission electron microscopy. Misfit dislocations with a periodicity of about 7 nm and Burgers vectors b5a^100& were observed at the interface. A high density of threading dislocations was present the films and these also had b 5a^100& . The data indicate that the threading dislocations are not generated as the result of half-loop climb from the deposit surface as proposed previously, but are instead formed when misfit dislocations are forced away from the interface during island coalescence. © 2004 American Institute of Physics. @DOI: 10.1063/1.1664035#