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ST6 - Strong enhancement of In-Field Critical Current Density at 20K in MgB2 with Minute Additions of Dy2O3 and B4C

Strong enhancement of In-Field Critical Current Density
at 20K in MgB2 with Minute Additions of Dy2O3 and B4C

P. Mikheenko(1,2), S. K. Chen(1), J. L. MacManus-Driscoll(1)

(1) Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, e-mail: [email protected]
(2) Metallurgy and Materials, School of Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK

Abstract - Minute additions of a combination of Dy2O3 and B4C have been used to enhance both pinning and upper critical field in MgB2 to the level suitable for MRI applications at 20 K. A delicate balance of Dy2O3 and B4C additions is required to improve pinning without significantly reducing connectivity between grains. The Dy2O3 nanoparticles react with B to form 10-15 nm DyB4 nanoparticles, while B4C supplies carbon into MgB2 crystal lattice and increases the upper critical field. The optimum level of Dy2O3 and B4C additions is ~0.5 wt. % of Dy2O3 and 0.04 wt. % of B4C, yielding a Jc (20K) of 105A.cm-2 at 2.7 T.

Manuscript received September 5, 2007; accepted October 15, 2007. Reference No. ST6, Category 2
Published in Appl. Phys. Lett. 91, 202508,2007