Comparison Between Al and C Substitutions in the Upper Critical Field of MgB2 Single Crystals

초록

The effect of Al and C substitutions on the upper critical fields H-c2, of MgB2 single crystals has been investigated. Despite similar suppression of the transition temperature T-c with increasing Al and C concentrations, the effects of the two substitutions on H-c2 are totally different. C substitution considerably increases H-c2(T) while Al substitution decreases H-c2(T). Based on the parameters obtained by fitting experimental data to the dirty-limit two-gap theory, we discuss the difference between the two substitutions in terms of impurity scattering.

키워드