Effects of Carbon Doping on Trapped Magnetic Field of MgB$_{2}$ Bulk Prepared by in-situ Hot Isostatic Pressing Method

We report the effects of carbon doping on the trapped field properties of MgB
₂
bulks doped with graphite (C) and B
₄
C, which were prepared by an in-situ hot isostatic pressing method. The trapped fields, BT's were degraded by the graphite and B
₄
C doping above 15K, which was predominantly due to the lowered T
_c
by the C substitution. However, the slope of BT(T) and the irreversibility line, Birr(T), determined from the resistive transitions indicated that the BT of the graphite-doped bulk was expected to exceed that of the pristine bulk below 15 K. Contrary to the literature by other groups, B
₄
C did not enhance the vortex pinning properties.