High upper critical field and irreversibility field in MgB2 coated-conductor fibers

We report on structural and superconducting properties of round MgB2 coated-conductor fibers deposited by hybrid physical-chemical vapor deposition on SiC fibers. The coating is polycrystalline and composed of elongated crystallites with dimensions less than 1 mu m in length and 0.2 mu m in width. The pure MgB2 fiber shows a zero-resistance T-c of 39.3 K. The carbon-alloyed fibers show a high upper critical field of 55 T at 1.5 K and a high irreversibility field of 40 T at 1.5 K. The result demonstrates great potential of MgB2 coated conductors for superconducting magnets.