Enhanced 2G HTS wire performance

In an ongoing collaborative research and development agreement (CRADA) with Los Alamos National Laboratory (LANL), STI and LANL produced a 2G HTS wire sample that demonstrates exceptional in-field critical current values. This world-class current-carrying capability in high magnetic field demonstrates the effectiveness of STI's HTS fabrication process at producing 2G HTS wire for demanding applications such as superconducting fault current limiters and high-power wind turbine generators.

STI produced a 2G HTS coated conductor sample on a LANL template that exhibits a minimum critical current of 228 amperes (A) at a temperature of 65 kelvin (K) in an applied magnetic field of 3 tesla (T), corresponding to 256 A per centimeter (cm)-width. This critical current is the minimum value as a function of magnetic field angle. The maximum critical current of this sample at 65 K exceeded 404 A per cm-width for a 3-T magnetic field oriented parallel to the coated conductor surface; this latter current value was limited by the amount of current supplied by the measurement apparatus. In a 5-T field at 65 K, the coated conductor exhibited a minimum critical current of 143 A per cm-width and a maximum critical current of 322 A per cm-width. The measurements were performed at LANL's Superconductivity Technology Center in Los Alamos, NM.

Dr. Brian Moeckly, Director of Materials Research and Development at STI, commented: "Achievement of this level of current-carrying capability in high magnetic field is a critical milestone in our development of 2G HTS wire. In addition, we fabricated this sample using a straightforward HTS structure; we did not need to add additional elements or so-called artificial pinning centers to the coated conductor to obtain this result. While these measurements were performed on a small sample, we believe that the outstanding properties of this wire can be maintained upon scale-up of our processes to long-length 2G HTS wire production."

Dr. Ken Marken, Superconductivity Technology Center Leader at LANL, added: "We are excited to verify these test results that confirm that STI's HTS deposition process produces 2G HTS wire with state-of-the-art superconducting properties."

STI's strategic 2G HTS wire program is utilizing its specialized HTS material deposition processes and volume manufacturing expertise to produce energy-efficient, cost-effective, and high-performance 2G HTS wire for next generation power applications. STI fabricates 2G HTS wire using its proprietary deposition technology known as reactive coevaporation with cyclic deposition and reaction (RCE-CDR). This specific sample of 2G HTS wire is 8.9 millimeters wide x 4.4 microns thick and was grown on a 1-cm-wide x 4-cm-long template provided by Los Alamos National Laboratory (LANL). This simplified template contained a reduced number of layers compared to competing 2G HTS wire technologies. The template consisted of a non-magnetic nickel-alloy substrate followed by layers of only two materials: a solution-deposition planarization (SDP) layer and an ion-beam assisted deposition (IBAD) layer. An advantage of the RCE-CDR technology is that it allows high-performance 2G HTS wire to be grown on these simplified templates. STI believes that this simplified template platform combined with STI's RCE-CDR process results in a superior high-yield, low-cost 2G HTS wire technology.

Source: Superconductor Technologies Inc.