Identification of octahedral configuration in strained SrRuO3 thin films

The compressively strained (2 2 0)-oriented SrRuO3 epitaxial thin films were grown on c-plane SrTiO3 substrates using pulsed laser deposition. Temperature-dependent lattice changes associated with structural phase transition were investigated through in-situ X-ray diffractions with varying temperature ranges from 25 to 650 °C under atmospheric conditions. Strong modulation of the in-plane lattices between the strained SrRuO3 thin film and SrTiO3 substrate was observed. The structural phase transition from pseudo-orthorhombic to the tetragonal structure was determined at around 285 °C and epitaxial strain was persistent during the structural phase transition in the fully strained SrRuO3/SrTiO3 heterostructured thin film. Crystal symmetry and the corresponding RuO6 octahedral configurations were verified that the compressively strained SrRuO3 thin film has pseudo-orthorhombic (monoclinic, P21/m, #11) structure with the BO6 configuration of a+a–c– at 25 °C and tetragonal (I4/mcm, #140) with the octahedral tilt of a0a0c– above 285 °C through structural model calculations based on the diffraction data of 20 individual half-order peaks.