Phase transformation of octahedral tilted monoclinic SrRuO_3 and tetragonal SrRuO_3 thin film on SrTiO_3 substrate

摘要

We investigated phase behaviors of octahedral tilted monoclinic and tetragonal SrRuO_3 (SRO) thin film on SrTiO_3 (STO) (001) substrate using the in-situ X-ray diffraction techniques. The monoclinic and tetragonal SRO thin films were epitaxially grown on the STO with a compressive strain. The oxygen octahedral structure of MSRO and TSRO films were octahedral notation of a~-a~-c~+and a~0a~0c~-, respectively. To investigate the octahedral distortion angle, the phase transformation, and the crystal structure, we measured the 002 Bragg reflection along the substrate normal direction and the 103 Bragg reflection and 2.5 0 1.5 half integer Bragg reflection along the off-specular direction. The phase transformation from the monoclinic to the tetragonal structure occurred at approximately 200 °C with second order transition behavior. Conversely, the phase transformation of TSRO thin films did not occur in the range from RT to 250 °C.