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- Title
Superconducting Characteristics of Polycrystalline Magnesium Diboride Ceramics Fabricated by a Spark Plasma Sintering Technique.
- Authors
Seung Hwan Shim; Kwang Bo Shim; Jong-Won Yoon
- Abstract
Highly densified MgB2 superconductors were successfully fabricated using a spark plasma sintering (SPS) technique, and their superconductivity with respect to microstructural evolution was evaluated. Full densification with final density close to the theoretical density was achieved at a temperature of 1000 °C within a total SPS processing time of 40 min. Both an MgB2 specimen sintered at 1000°C for 30 min and one sintered at 1050°C for 10 min exhibited a high critical transition temperature (Tc) similar to that of an MgB2 single crystal (39 K), and a very sharp superconducting transition width (ΔT) less than 0.5 K. In addition, high critical current densities (Jc) of 7.7 × 105 A/cm² in a field of 0.6 T at 5 K and of 8.3 × 104 A/cm² in a field of 0.09 T at 35 K were obtained. These excellent superconducting characteristics of the SPS-processed MgB2 are attributed to uniformly distributed secondary MgO phase nanoparticles and well-developed dislocations in the microstructure that may act effectively as extrinsic flux pinning sites, resulting in the strong pinning force showing a high Jc of 8.7 &time;s 104 A/cm² even in the condition of a field of 4 T at 5 K.
- Subjects
SUPERCONDUCTORS; POLYCRYSTALLINE semiconductors; CERAMICS; SINTERING; NANOPARTICLES; DISLOCATIONS in metals
- Publication
Journal of the American Ceramic Society, 2005, Vol 88, Issue 4, p859
- ISSN
0002-7820
- Publication type
Article
- DOI
10.1111/j.1551-2916.2005.00220.x