The effect of CO<sub>2</sub> in the processing atmosphere of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub>
E K Chang; E F Ezell; M J Kirschner; E K Chang; BOC Group Inc., Murray Hill, NJ, USA; E F Ezell; BOC Group Inc., Murray Hill, NJ, USA; M J Kirschner; BOC Group Inc., Murray Hill, NJ, USA
Журнал:
Superconductor Science and Technology
Дата:
1990-08-01
Аннотация:
Processing atmospheres of up to 1% CO<sub>2</sub>-doped oxygen were employed to study the effect of carbon contamination on the superconducting properties of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub>. While 100 p.p.m. CO<sub>2</sub> did not show any adverse effect, J<sub>c</sub> decreased drastically in 1000 p.p.m. CO<sub>2</sub>. The sample processed in 1% CO<sub>2</sub>-doped oxygen was non-superconducting at 77 K. X-ray diffraction indicated a tetragonal structure and the oxygen content of this sample was found to be 6.65 by iodometric titration. The microstructural appearance suggests that a continuous grain boundary film may have formed which is less pervious to oxygen at the lower temperatures used for annealing during sample preparation.
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