Laser Micromachining of Coated YBa2Cu3O6+x Superconducting Thin Films
  Over the last decade advances in high temperature superconducting (HTS) materials have generated a renewed optimism in the use of this technology in future high-power applications including motors, generators, and power transmission. The most promising superconducting material, YBa2Cu3O6+x (YBCO), has demonstrated current density capacity as high as 106 A/cm2 and is typically deposited epitaxially as a thin film on a buffered metallic substrate. The coated conductor architecture Ag/YBCO/Buffer/Ni-based substrate, as does other heteromaterials, introduces unique challenges to the laser micromachining process. In the present study, optimization of the laser micromachining process for machining grooves extending through the YBCO into the buffer layer is considered. A frequency tripled diode-pumped solid-state Nd:YVO4 laser at 355 nm is used in conjunction with both fixed and scanning optical systems. The dependence of cut quality, dimension, and local damage to the YBCO layer on the laser processing parameters including focal spot size, pulse overlap, and fluence will be discussed. Preliminary experimental results indicate that laser micromachining may be used as a reliable process for patterning of superconducting tapes. 
Kenneth E. Hix, Matthew C. Rendina, James L. Blackshire, and George A.   Levin