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Oxygen diffusion coefficients for Sr{sub 2}AlTaO{sub 6}: Ramifications on HTSC multilayer processing

Book ·
OSTI ID:392182
; ; ; ; ; ;  [1]; ;  [2]
  1. Army Research Lab., Fort Monmouth, NJ (United States)
  2. Conductus, Inc., Sunnyvale, CA (United States)

The authors have studied the rate of oxygen diffusion through Sr{sub 2}AlTaO{sub 6} (SAT), a buffer and dielectric layer used in high critical temperature superconducting (HTSC) structures. An epitaxial bilayer film of SAT on YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) was deposited onto an (001) oriented single crystal LaAlO{sub 3} substrate using the pulsed laser deposition technique. The rate of oxygen diffusion through the bilayer was investigated over the temperature range 415 to 675 C by post deposition annealing individual sections of the bilayer in 1/3 atm of {sup 18}O enriched molecular oxygen gas. Secondary ion mass spectroscopy was used to depth profile {sup 18}O and {sup 16}O in each sample. Oxygen diffusion coefficients for SAT at 418, 510, 570 and 673 C were determined to be roughly (0.93, 6.31, 26.6 and 75.3) {times} 10{sup {minus}16} cm{sup 2} s{sup {minus}1}, respectively. Since these diffusion rates can limit oxygen intake into underlying YBCO films, SAT may be an inappropriate choice as a dielectric candidate for use in an HTSC multilayer device technology and will at best require development of suitable post annealing schemes to oxygenate underlying YBCO layers.

OSTI ID:
392182
Report Number(s):
CONF-951155--; ISBN 1-55899-304-5
Country of Publication:
United States
Language:
English