NMR study of vortex dynamics in LuNi2B2C

Abstract

B-11- and C-13-pulsed nuclear magnetic resonance (NMR) measurements have been performed on two single crystals of LuNi2B2C and (LuNi2B2C)-C-13 superconductors to investigate the vortex dynamics. B-11 NMR for the unenriched crystal, LuNi2B2C, shows a single peak. All data of B-11 NMR exhibit significant features characteristic of vortex lattice and fluctuation. On the other hand, C-13 NMR for the enriched crystal, (LuNi2B2C)-C-13, evolves to double peaks below T-c. All NMR data for the broad peak of C-13 NMR are consistent with those of B-11 NMR indicating that this part comes from a superconducting phase. On the contrary, the narrow peak of C-13 NMR is found to originate from an impure phase. This suggests that crystallinity is deteriorated during C-13 enrichment into the crystal. (C) 2003 Elsevier B.V. All rights reserved.