Benzoic Acid Doping to Enhance Electromagnetic Properties of Superconductors

• Published in: IEEE transactions on applied superconductivity Vol. 17; no. 2; pp. 2778 - 2781
• Main Authors: Li, W.X., Li, Y.., Zhu, M.Y., Chen, R.H., Xu, X.., Yeoh, W.K., Kim, J.H., Dou, S.X.
• Format: Journal Article
• Language: English
• Published: IEEE 01.06.2007
• Subjects: Additives; Aromatic acids; benzoic acid; Boron; Critical current density; Doping; Electromagnetic forces; Flux pinning; Lattices; Microstructure; Powders; superconductivity; Temperature; {\rm MgB}_{2}
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2007.899379

The effect of benzoic acid doping on lattice parameters, microstructure, critical temperature (T c ), critical current density (J c ) and flux pinning force of MgB 2 has been studied. In this work we used benzoic acid as an example of aromatic acids as an additive to MgB 2 . For different sintering process, actual carbon (C) substitution for boron (B) was estimated to be from 3.5 at% to 5.0 at% of B while T c dropped about 2-4 K. The advantages of aromatic acid doping include homogeneous mixing of precursor powders, avoidance of expansive nano-additives, production of highly reactive C and significant enhancement in J c of MgB 2 , compared to undoped samples. High level C substitution of B can induce the MgB 2 crystals grow into bar shape microstructure. The J c value of 1.5 times 10 4 Acm -2 at 5 K and 8 T for preheated 10 wt% C 7 H 6 O 2 doped MgB 2 sample is higher than that of the undoped MgB 2 by a factor of 13. As there are numerous aromatic acids readily available this finding has significant ramifications not only for the fabrication of MgB 2 but also for many C based compounds and composites.