RAPID COMMUNICATION: Significant enhancement of Hc2 and Hirr in MgB2+C4H6O5 bulks at a low sintering temperature of 600 °C
Abstract
We report the carbon (C) substitution effects of MgB2+10 wt% C4H6O5 (malic acid) on the lattice parameters, critical temperature (Tc), upper critical field (Hc2), and irreversibility field (Hirr) as a function of sintering temperature in the range from 600 to 900 °C. The additive C4H6O5 as the C source resulted in a small depression in Tc, but significantly increased the C substitution level, and hence improved the Hc2 and Hirr performance at a low sintering temperature of 600 °C in conjunction with a short sintering period of 4 h. In addition, the low-temperature sintering process resulted in small grain size and higher impurity scattering compared to a pure MgB2 superconductor. These effects promote flux pinning.
- Publication:
-
Superconductor Science Technology
- Pub Date:
- August 2007
- DOI:
- 10.1088/0953-2048/20/8/L03
- Bibcode:
- 2007SuScT..20L..51H