SUPPRESSION OF SUPERCONDUCTIVITY IN LI(TI1-XVX)(2)O-4

LiTi2O4 and LiV2O4 are both normal spinel structure oxides. LiTi2O4 is a superconductor with the transition temperature T-c as high as 13 K. While LiV2O4 shows metallic conduction and the magnetic susceptibilit y follows the Curie-Weiss law, suggesting localized magnetic moments. We report on the detailed electrical and magnetic properties of Li(Ti1 -xVx)(2)O-4 system for 0 less than or equal to x less than or equal to 0.05 with an emphasis on the low V concentration. As the V content is increased, the specimen exhibits lower T-c and undergoes a smooth tra nsition. For x = 0.05, the superconductivity is almost smeared out. Th e localized magnetic moment per V atom is estimated to be about 1.7 mu (B), which indicates V4+ State with S = 1/2. The localized magnetic mo ments, induced by the V-doping, are responsible for the pair breaking and the extremely sensitive destruction of the superconductivity. The decay of T-c as a function of V concentration is similar to AlMn and T hU. Pair breaking mechanism in the superconductivity in these specimen s is not interpreted simply in terms of the Abrikosov and Gor'kov theo ry.