Laser patterning of superconducting YBa 2 Cu 3 O 7–x thin films

Abstract

Epitaxial YBa₂Cu₃O_7–x thin films have been patterned using aKrF excimer laser. Contact masks and mask imaging have been used to obtain YBa₂ Cu₃O_7–x bridges 8–20 μm in width. The process has been carried out under different environmental and laser fluence conditions. The best morphology is obtained in vacuum and with the highest laser fluences. The material composition in the bridges depends strongly on the fluence but not on the environment. The composition edges become steeper as the fluence is increased over the ablation threshold. Mask imaging allows retention of the electrical properties of the original film in the bridges, with a critical temperature greater than 91 K, a transition width of 1·5 K, and a critical current density greater than 10⁶ A cm⁻² at 77 K. The bridges defined by contact masks have slightly inferior superconducting properties but they can be recovered by annealing in flowing oxygen.

MST/3224