Solid State Science and Technology, Vol. 17, No 1 (2009) 173-181

ISSN 0128-7389

COMPARATIVE STUDY ON THE CRITICAL CURRENT DENSITY OF MgB2 PREPARED BY MIXED BORON POWDERS

S. K. Chen1, K. P. Lim1, K. B. Tan2 and S. A. Halim1

1Physics Department, Faculty of Science, Universiti Putra Malaysia

43400, Serdang, Selangor, Malaysia.

2Chemistry Department, Faculty of Science, Universiti Putra Malaysia

43400, Serdang, Selangor, Malaysia.

 

ABSTRACT

Polycrystalline MgB2 was prepared from Mg and boron precursors consisting of boron powders with varying purity and form. Tc does not change largely for all samples. By replacing 10 wt.% of high purity amorphous boron with impure crystalline boron, comparable Jc to that of samples prepared from high purity amorphous boron powder alone can be obtained. High Jc can also be retained by replacing 20 wt.% of the high purity amorphous boron with impure amorphous boron. However, Jc decreases more rapidly with field by increasing the proportion of impure amorphous boron. By mixing both impure amorphous and crystalline boron powders even up to the proportion of 50 50 wt.%, the obtained MgB2 exhibit enhanced Jc compared to samples prepared from the respective boron powder alone. The enhancement in Jc at 6K and 20K is more pronounced for applied field ≤ 3T.

 

http://journal.masshp.net/wp-content/uploads/Journal/2009/Jilid%201/S.%20K.%20Chen%20173-181.pdf

 

REFERENCES

[1]. J. Nagamatsu, N. Nakagawa, T. Muranaka, Y. Zenitani and J. Akimitsu (2001). Superconductivity at 39 K in magnesium diboride. Nature 410, 63-64.

[2]. D.C. Larbalestier, L.D. Cooley, M.O. Rikel, A.A. Polyanskii, J. Jiang, S. Patnaik, X.Y. Cai, D.M. Feldmann, A. Gurevich, A. Squitieri, M.T. Naus, C.B. Eom, E.E. Hellstrom, R.J. Cava, K.A. Regan, N. Rogado, M.A. Hayward, T. He, J.S. Slusky, P. Khalifah, K. Inumaru, and M. Haas (2001). Strongly linked current flow in polycrystalline forms of the superconductor MgB. 2Nature 410, 186-189.

[3]. J. Wang, Y. Bugoslavsky, A. Berenov, L. Cowey, A.D. Caplin, L.F. Cohen, J.L. MacManus-Driscoll, L.D. Cooley, X. Song and D.C. Larbalestier (2002). High critical current density and improved irreversibility field in bulk MgB2 made by a scaleable, nanoparticle addition route. Appl. Phys. Lett. 81, 2026-2028.

[4]. S.X. Dou, S. Soltanian, J. Horvat, X.L. Wang, S.H. Zhou, M. Ionescu, H.K. Liu, P. Munroe and M. Tomsic (2002). Enhancement of the critical current density and flux pinning of MgB2 superconductor by nanoparticle SiC doping. Appl. Phys. Lett. 81, 3419-3421.

[5]. W.K. Yeoh, J. Horvat, S.X. Dou and V. Keast (2004). Strong pinning and high critical current density in carbon nanotube doped MgB. 2Supercond. Sci. Technol. 17, S572-S577.

[6]. Y. Zhao, Y. Feng, T.M. Shen, G. Li, Y. Yang and C.H. Cheng (2006). Cooperative doping effects of Ti and C on critical current density and irreversibility field of MgB2, J. Appl. Phys. 100, 123902-5.

[7]. P. Lezza, C. Senatore and R. Flukiger (2006). Improved critical current densities in BC doped MgB based wires. 42Supercond. Sci. Technol. 19, 1030-1033.

[8]. J.M. Rowell (2003). The widely variable resistivity of MgB samples. 2Supercond. Sci. Technol. 16, R17-R27.

[9]. R.A. Ribeiro, S.L. Bud'ko, C. Petrovic and P.C. Canfield (2002). Effects of stoichiometry, purity, etching and distilling on resistance of MgB pellets and wire segments2. Physica C 382, 194-202.

[10]. S.K. Chen, K.A. Yates, M.G. Blamire and J.L. MacManus-Driscoll (2005). Strong influence of boron precursor powder on the critical current density of MgB.2 Supercond. Sci. Technol. 18, 1473-1477.

[11]. P. Mikheenko, S.K. Chen and J.L. MacManus-Driscoll (2007). Minute pinning and doping additions for strong, 20 K, in-field critical current improvement in MgB2. Appl. Phys. Lett. 91, 202508-3.