Title :
Temporal stability of circulating current in thin film Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/ and YBa/sub 2/Cu/sub 3/O/sub 7/
Author :
Wheatley, R.W. ; Hennessy, M.J. ; Hung Bin Zou
Author_Institution :
Intermagnetics Gen. Corp., Latham, NY, USA
fDate :
3/1/1997 12:00:00 AM
Abstract :
The temporal stability of trapped transport current in annular thin film Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/ (TBCCO) and YBa/sub 2/Cu/sub 3/O/sub 7/ (YBCO) wafers has been accurately measured and has been found to be of suitable quality for the stringent requirements of nuclear magnetic resonance (NMR) magnets. No detectable decay, to the limit of the experimental apparatus (2*10/sup -14/ /spl Omega/), was detected in those wafers with transport current at or below the critical current density J/sub c/. The critical current density, as previously determined from 12 /spl mu/m meander lines, was confirmed in a wafer with a width of 1.9 cm. The profile of trapped magnetic field resulting from induced current was modeled in order to assess its effect on the uniformity of an NMR magnet.
Keywords :
NMR spectroscopy; barium compounds; calcium compounds; critical current density (superconductivity); high-temperature superconductors; superconducting magnets; superconducting thin films; thallium compounds; yttrium compounds; NMR magnet; TBCCO; Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/; YBCO; YBa/sub 2/Cu/sub 3/O/sub 7/; annular thin film wafer; circulating current; critical current density; temporal stability; transport current; trapped magnetic field; Critical current density; Current measurement; Magnetic films; Magnets; Nuclear magnetic resonance; Nuclear measurements; Semiconductor device modeling; Stability; Transistors; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
