Geometric-shape-dependent structural transition behavior in (110) SrRuO3 epitaxial thin films

We performed structural investigations of epitaxially grown SrRuO3 films with geometric shapes of one-dimensional stripes and a two-dimensional layer, focusing on how the geometric shapes affect the structural transition behavior from the high-temperature pseudo-cubic phase to the low-temperature orthorhombic one. From the temperature dependence of the out-of-plane lattice parameter of the films, we found that the structural transition in the stripe-shape film occurs in a narrower temperature range as compared to that in the layer-shape film. Detailed reciprocal space mappings reveal that in the stripe-shape film, crystallographic twins are formed in the orthorhombic phase due to the strain relaxation along the [1-10](ortho_SRO) direction and as a consequence the transition occurs in the narrower temperature range. In contrast, the layer-shape film is fully strained and maintains a single crystallographic domain across the transition. The results indicate that the strain effect on the structural transition behavior is strongly dependent on the geometric shapes of the films. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4716029]