We report that when (La,Sr)MnO3 films grown on orthorhombic (110)o DyScO3 (DSO) substrates once reach a critical thickness, anisotropic patterned cracks are introduced which propagate parallel to [1-10]o direction. The typical surface morphology and cross-sectional TEM are examined in order to clarify the formation of these cracks. The cause of crack propagation through the film and into the substrate is identified as the underlying large anisotropic strain and relatively low stiffness of DSO substrates. The electrical conduction in the crack region is found to be several orders of magnitude higher than that in the uncracked areas of the film. The energy dispersive x-ray-verified La0.7Sr0.3MnO3 deposited into cracks may be responsible for the anomalous conducting behaviors. Finally, a simple model is constructed for estimating substrate fracture toughness and calculating an upper bound of film fracture toughness.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)