Laser writing of superconducting patterns on YBa2Cu3Ox films

A novel process for the direct laser writing of thin‐film high Tc patterns is demonstrated. The process consists of deposition of a high quality film (308 nm laser ablation from a YBa2Cu3Ox target with a 750 °C substrate temperature and a 150 mTorr O2 ambient), annealing in an inert atmosphere (Ar at 400 °C for 5–20 min) to reduce the oxygen content and depress or eliminate the superconducting transition temperature, and direct‐write laser heating (1.06 μm at ≊0.5 kW/cm2 for ≊5 min) in an oxygen atmosphere at ≊590 Torr to selectively regenerate the high Tc material. rf eddy current and four‐point resistivity probe results confirm this process for both SrTiO3 and LaAlO3 substrates. Scanning electron micrographs indicate that this is a very mild processing sequence with no observable changes in film morphology.