Friday, 2D-13, 5:10-5:20

Characterization and Analysis of Coated Conductors: Toward Improved Performance

D. K. Christen

J. R. Thompson, Y. L. Zuev, S-H. Wee, A. Goyal

Oak Ridge National Laboratory, Oak Ridge, TN 37831
865-574-6269, 865-574-6263, christendk@ornl.gov

With significant advances in the processing of 2G HTS coatings for the achievement of strong-pinning defects structures, it is important to adequately assess and relate the superconducting properties of prototype materials to the potential applications needs, and to provide feedback for optimization and tailoring of specific properties. Of particular interest are the characteristics and understanding of anisotropic flux pinning provided by self-assembled extended defects, when coupled with the intrinsic electronic anisotropy of RBCO cuprates. Recently, we have found that these competing effects can lead to near-isotropic critical currents under specific operational parameters. A model that adequately describes the phenomenon may provide insight into means to fine-tune the material properties for nearly isotropic performance characteristics at an interval of preferred field and temperature.

Because of practical difficulties in measuring transport properties of short prototype samples at lower temperatures and electric field levels, a new component of the work involves methodologies for characterization at previously inaccessible field, temperature, and dissipative regimes. These techniques include contactless dc magnetometry that determine orientation-dependent critical currents, and can also be extended to electric field levels that are several orders-of-magnitude lower than in transport, more commensurate with the very low dissipation levels required for coil-based devices such as motors, generators, air-gap transformers, SMES, etc. Results will be discussed in the context of providing pathways for further improvement of 2G performance.

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