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.