Oxygen in-diffusion in 2223 phase BPSCCO superconductor oxide

✍ Scribed by C.J. Zhou; X.M. Xie; T.G. Chen

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 643 KB
• Volume: 191
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(92)90646-t

✦ Synopsis

The oxygen in-diffusion process in the oxygen-deficient single 2223 phase BiLrPbo.4Sr2Ca2Cu~O~ ceramic oxide has been investigated by in situ resistance measurements during ramp annealing and isothermal annealing in flowing oxygen. It is observed that the oxygen in-diffusion is much faster than the out-diffusion. A one-dimensional diffusion model of oxygen vacancy is proposed, and a good approximate solution for Fick's second law of diffusion, considering the distance dependence of diffusivity, D, is obtained as C= I -(8/n 2) ( 1 + 8D't/F) -~. The activation energy for oxygen in-diffusion process is determined to be 0.86 eV, and the diffusivity D is closely related to the average concentration of the oxygen vacancy which decreases with annealing time during oxygen replenishment. Finally, we have discussed a simple mechanism of oxygen vacancy diffusion along the a direction in the Bi2-O: layers.