Refreshment of SrTiO3 Substrate for Layer Peeling-off using Sacrificial Sr3Al2O6

The use of water-soluble sacrificial layer of Sr3Al2O6 has tremendously boosted the research on freestanding functional oxide thin films, especially thanks to its ultimate capability to produce high-quality epitaxial perovskite thin films. However, the costly single-crystalline substrates, e.g., SrTiO3, are generally discarded after obtaining the freestanding thin films. Here, it is demonstrated that the SrTiO3 substrates can be recycled to fabricate La0.7Sr0.3MnO3 films with nearly identical structural and electrical properties. After attaining freestanding thin films, the residues on SrTiO3 can be removed by 80 degrees C hot water soaking and rinsing treatments. Consequently, the surface of SrTiO3 reverted to its original step-and-terrace structure.