Preparation of Atomically Smooth SrTiO₃ Substrates

SrTiO3 has been used as a substrate to grow thin films of materials including high-temperature superconductors such as cuprates, ferromagnetic oxides such as manganites, and ferroelectric oxides such as BaTiO3. The use of SrTiO3 as a substrate for the deposition of manganite thin films provides an excellent template for observing unique effects observed only in ferromagnets, such as the anomalous and planar Hall effects. The as-received SrTiO3 substrates require a process that prepares atomically smooth surfaces for thin film deposition. This study focuses on using ultrasonic cleaning, water annealing, and thermal annealing in air to prepare SrTiO3 substrate surfaces and verifying their smoothness at the atomic scale using atomic force microscopy.