In situ synchrotron X-ray studies of ferroelectric thin films

In situ synchrotron X-ray scattering was used to observe both the growth of PbTiO₃ films by metal-organic chemical vapour deposition and the behaviour of the ferroelectric phase transition as a function of film thickness. The dependences of growth mode and deposition rate on gas flows and substrate temperature were determined by homoepitaxial growth studies on thick films (> 50 nm). These studies facilitated the growth of thin coherently strained PbTiO₃ films on SrTiO₃ (001) substrates, with thicknesses ranging from 2 to 42 nm. Experiments on the ferroelectric phase transition as a function of film thickness were carried out in these films under controlled mechanical and electrical boundary conditions.