Charge-ordered Pr0.5Ca0.5MnO3 thin films epitaxially grown on SrTiO3 (100) substrates were prepared by a two-step growth technique which resulted in a 10nm thick first layer and a 70nm-thick main layer. The dislocations in the as-received films were investigated using conventional and high-resolution transmission electron microscopy. Pure-edge misfit dislocations with Burgers vectors a<011> and line directions <100> were found to be the major interfacial defects responsible for the full misfit relief in the Pr0.5Ca0.5MnO3 films. These dislocations constitute a square grid of dislocation lines parallel to the Pr0.5Ca0.5MnO3/SrTiO3 interface. In contrast, two types of dislocations were identified within the first layer. One was of edge type with Burgers vectors a<110> and line directions <001>; the other, of screw-type with Burgers vectors a<110> and line directions <110>. Cross-slip of the latter might contribute to the multiplication of misfit dislocations necessary for a total misfit relaxation. Few threading dislocations were observed in the main layer. The dislocation configurations in the films were considered in detail.

Dislocations in Charge-Ordered Pr0.5Ca0.5MnO3 Epitaxial Thin Films Prepared by a Two-Step Growth Technique. Y.L.Zhu, X.Wang, M.J.Zhuo, Y.Q.Zhang, X.L.Ma: Philosophical Magazine Letters, 2010, 90[5], 323-36