Enhancement of critical current density in low level Al-doped MgB2

A BERENOV; A SERQUIS; X. Z. LIAO; Y.T.ZHU; D. E. PETERSON; Y BUGOSLAVSKY; K. A. YATES; M G BLAMIRE; L F COHEN; J L MACMANUS-DRISCOLL1

SUPERCONDUCTOR SCIENCE AND TECHNOLOGY

IOP Publishing Ltd

Año: 2004 vol. 17 p. 1093 - 1096

0953-2048

Two sets of MgB2 samples doped with up to 5 at.% of Al were prepared indifferent laboratories using different procedures. Decreases in the ‘a’ and‘c’ lattice parameters were observed with Al doping, confirming Alsubstitution onto the Mg site. The critical temperature (Tc) remained largelyunchanged with Al doping. For 1–2.5 at.% doping, at 20 K the in-fieldcritical current densities (Jcs) were enhanced, particularly at lower fields. At5 K, the in-field Jc was markedly improved; for example at 5 T Jc wasenhanced by a factor of 20 for a doping level of 1 at.% Al. The improved Jcscorrelate with increased sample resistivity, which is indicative of an increasein the upper critical field, Hc2, through alloying.