Enhancement of the irreversibility field by carbon substitution in single crystal MgB${}_2$

E. Ohmichi, T. Masui, S. Lee +2

We report the detailed study of the irreversibility field {\hirr} of single crystals of Mg(B${}_{1-x}$C${}_x$)${}_2$ ($x$=0, 2, 3.5, 5 and 7%) in strong magnetic fields of up to 40 T.…