DISLOCATION DENSITY IN SrTiO3 FILM GROWN ON DyScO3 BY PULSE LASER ABLATION

SrTiO3 films are fabricated on DyScO3 substrates by pulse laser deposition. In situ X-ray diffraction (XRD) is used to characterize the thermal expansion coefficient at low temperature. The abnormal behavior in lattice parameter at 80 K may be the hint of a phase transition. High resolution XRD is performed to detect the two kinds of dislocations, i.e. screw and edge. Results show that the density of edge dislocation is a little larger than that of the screw one. The total dislocation density has the order of about 108 cm-2. Edge dislocation density decreases with the increase of the film thickness. We argue that the ratio between these two dislocation densities results in the growth mode of the film.