Enhanced supercurrents above 100 K in mercury cuprates via fission of mercury
- IBM T.J. Watson Research Center, Yorktown Heights, NY (United States)
- Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics
- UES Inc., Dayton, OH (United States)
- Los Alamos National Lab., NM (United States)
- Houston Univ., TX (United States). Texas Center for Superconductivity
Large-scale technological success of high-temperature superconductors will ultimately be decided by their capacity to sustain large critical current densities J{sub c} in high magnetic fields. There are two principal factors controlling current conduction. One is regions of weaker superconductivity (weak links) at the grain boundaries in polycrystalline materials. Another is easy motion of magnetic vortices in the bulk -- the result being energy dissipation and losses. Each of these factors is a challenge to overcome, for their origin is intrinsic: i.e. short superconducting coherence length {xi}, large anisotropy, large thermal fluctuations (related to high transition temperature T{sub c}), and perhaps even a d-wave character of the superconducting ground state. For these reasons, in spite of the highest T{sub c}`s (> 130 K), mercury cuprates HgBa{sub 2}Ca{sub n{minus}1}Cu{sub n}O{sub 2n+2+{delta}} with n = 1, 2 or 3 adjacent CuO layers (Hg-1201, 01212, or -1223) still have relatively low-lying irreversibility lines (suppressed by a strong 2-D nature of the vortex structure), above which J{sub c} vanishes. Here, the authors demonstrate a method by which they expand the useful range to T > 100 K (higher than in Y-, Bi-, or Tl-based materials) and boost J{sub c} by orders of magnitude in fields of several Tesla -- namely fission of Hg nuclei within Hg-cuprates with energetic (0.8 GeV) protons. This technologically viable process allows doping these cuprates with strongly pinning columnar defects.
- Research Organization:
- Oak Ridge National Lab., Solid State Div., TN (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 672052
- Report Number(s):
- ORNL/CP-98138; CONF-971227-; ON: DE98005582; BR: KC0202020; TRN: 99:000803
- Resource Relation:
- Conference: 8. US/Japan workshop on high temperature superconductivity, Tallahassee, FL (United States), 8-10 Dec 1997; Other Information: PBD: May 1998
- Country of Publication:
- United States
- Language:
- English
Similar Records
Recent progress in Hg-based cuprates
Pressure-induced enhancement of T[sub c] above 150 K in Hg-1223