Temperature Dependent Octahedral Tilting Behaviors of Monoclinic and Tetragonal SrRuO₃ Thin Films

We used in-situ synchrotron X-ray scattering to investigate phase transformations of octahedral tilted monoclinic SrRuO3 (MSRO) and tetragonal SRO (TSRO) thin films on SrTiO3 (STO) substrates. The octahedral tilted MSRO thin films were highly crystalline and the monoclinic distortion angle was 0.45 ◦ . The phase transition temperature from the MSRO to TSRO phase occurred at approximately 200 ◦ C as a second order transition. Conversely, no phase transformations of the TSRO thin film occurred within the range from RT to 250 ◦ C. The octahedral RuO6 rotation was strongly affected by the phase transformation in the SRO thin films.