Stair-rod dislocations in perovskite films on LaAlO3 substrates

Two types of stair-rod dislocation formed at junctions of {111} stacking fa ults in SrTiO3-SrRuO3 two-layer films on LaAlO3 substrates have been studie d by high-resolution transmission electron microscopy. The first type, form ed by the interaction of two stacking faults situated at the flat SrRuO3-La AlO3 interface without any step, has a Burgers vector (a/3)[110]. The other type, formed by the interaction of two stacking faults, of which one start s from the SrRuO3-LaAlO3 interface area involving an interface step, has a Burgers vector (a/3)[120]. The formation mechanism of the stair-rod disloca tions and the effect of the step are discussed.