Stress/Strain Induced Flux Pinning in Highly | Dense rm MgB 2 Bulks

• Published in: IEEE transactions on applied superconductivity Vol. 19; no. 3
• Main Authors: Zeng, R, Dou, Shi Xue, Lu, L, Li, W X, Poh, C K, Kim, J H, Horvat, J, Shi, D Q, Wang, J L, Munroe, P, Wang, X F, Zheng, R K, Ringer, S P, Rindfleisch, M, Tomsic, M
• Format: Journal Article
• Language: English
• Published: 01-01-2009
• Subjects: Borides; Flux pinning; Magnesium compounds; Nanostructure; Pinning; Purity; Strain; Stresses
• ISSN: 1051-8223
• DOI: 10.1109/TASC.2009.2019577

We have systematically studied the flux pinning behavior of MgB sub(2) bulks synthesized by direct diffusion of Mg into pressed pellets of high purity crystalline B powder, with and without mixing with C and SiC nanoparticles, at a reaction temperature of 850 super(deg)C for 10 hrs. All of the samples showed very high purity and high density, but their microstructure and flux pinning behavior showed significant differences. It was found that the pure MgB sub(2) agrees with the deltaT sub(c) pinning model, nano-C doped MgB sub(2) agrees with the deltal pinning model, while the SiC+MgB sub(2) composite agrees with the deltaepsiv pinning model (stress/strain field pinning), since the dominant micro-defects that influence the flux pinning in these three samples are different.