Laser Direct-Write for Low AC Loss High Temperature Superconductor Applications

Abstract

The use of high temperature superconductors (HTS) in applications such as power cables, fault current limiters, and electromagnets, has seen rapid growth in recent years. While HTS exhibit zero dc resistance, appreciable ac losses are observed when the HTS are subject to an applied ac magnetic field. By dividing the HTS films into thin filament arrays and creating periodic metallic cross-overs to allow for flux penetration, the ac loss of the HTS can be significantly reduced. The HTS, YBa2Cu3O7-x (YBCO), films were prepared from the metal organic decomposition of a trifluoroacetate-based (TFA) precursor solution onto buffered substrates, manufactured by AMSC. To deposit the TFA solutions onto the buffered substrates, a new laser direct-write (LDW) technique was developed. LDW is a non-contact, non-lithographic process that relies on the mask-less printing of functional materials, such as metallic inks. The transferred TFA precursor filaments were then decomposed and subsequently characterized. In addition to the deposition of TFA precursors onto buffered substrates, LDW was used to print silver lines for metallic crossovers onto HTS tapes. These results show LDW to be a promising technique for the fabrication and modification of high temperature superconductors.