20 research outputs found
Evaluation of YBaâCuâOâââ Bulk Superconductors for High Field Magnet Applications
Processing of YBCO single crystals was carried out by solidification of semi-liquid YBCO composition using a seeding technique. Microstructural characterization of the pinning centers was investigated by transmission electron microscopy. Characterization of single crystals was carried out, relating grain size and shape to the corresponding flux profiles. Current densities were calculated based on measured trapped fields. Once circulating currents were established, flux pumping and quenching experiments were conducted. These large single crystals will be incorporated into electromagnetic forming devices for use in the military and commercial aircraft manufacturing and service industries
Evidence of Doping-Dependent Pairing Symmetry in Cuprate Superconductors
Scanning tunneling spectroscopy (STS) studies reveal long-range spatial
homogeneity and predominantly -pairing spectral characteristics in
under- and optimally doped superconductors, whereas
STS on exhibits {\it
microscopic} spatial modulations and strong scattering near the Zn or Mg
impurity sites, together with global suppression of the pairing potential. In
contrast, in overdoped ,
-pairing symmetry is found, suggesting significant changes in
the superconducting ground-state at a critical doping value.Comment: 4 pages, 4 figures. Published in Physical Review Letters.
Corresponding author: Nai-Chang Yeh (e-mail address: [email protected]