Abstract
In situ electrical resistance measurements, differential thermal analysis, and x‐ray diffraction studies were carried out between room temperature and 950 °C on as‐grown amorphous insulating YBa2Cu3O7−x thin films. Results for the phase transformation reaction path are reported in order to optimize the post‐deposition annealing process. Amorphous‐to‐crystalline transformations were observed at 550 °C along with a reversible orthorhombic‐tetragonal transition near 670 °C. Eutectic melting above 850 °C was also noted, which restricts the maximum annealing temperature to around 850 °C.