The effect of hydrogenation on the superconducting transition temperature of MgB2

Hydrogenation of commercial MgB2 powder (superconducting transition temperature 38.2 K) at temperatures greater than or equal to 600 degreesC and hydrogen pressures up to 10 bar has lead to an increase in T-c, as determined by ac susceptibility measurements. Applied do fields reduced the transition temperature by a slightly larger value than that for the pure powder. Heating the MgB2 powder for 2 h at 600 degreesC in 10 bar of either helium or argon gas has also lead to an increase in the transition temperature. (C) 2002 Elsevier Science B.V. All rights reserved.