Phase transition from SrRuO3 to Sr3Ru2O7 by tuning oxygen pressure at low processing temperature

The epitaxial growth of Sr3Ru2O7 thin films in the Ruddlesden-Popper type remains a challenge as the growth temperature required for a typical pulsed laser deposition (PLD) process can be as high as 1100 degrees C. In this study, high quality Sr3Ru2O7 epitaxial thin films were obtained using PLD with a single SrRuO3 target. By adjusting the oxygen partial pressure, the structure underwent a phase transition from SrRuO3 to Sr3Ru2O7 facilitated by the formation and development of oxygen and ruthenium vacancies. Remarkably, for the first time, high-quality Sr3Ru2O7 thin films with good crystalline quality were successfully grown at a low temperature of 680 degrees C on SrTiO3 substrates.