Effects of ball-mill processing on the superconductivity of sucrose doped MgB2

Good critical current density, J(c)(H), performance is found in sucrose doped MgB2 samples produced by both ball-milling and hand milling. It has been found that the J(c) of the ball-milled doped MgB2 sample was 7.0 x 10(3) A cm(-2) at 5K and 8T, which is more than two times higher than for hand-milled doped MgB2 and a factor of 70 higher than for the pure reference sample made from as-supplied amorphous boron powder. Significant improvement in J(c) at high fields is attributed to the upper critical field, H-c2, enhancement caused by the increased disorder. (C) 2009 Elsevier B.V. All rights reserved.