Emergence of Antiferromagnetic Correlation in LiTi2-xVxO4 via 7Li NMR
  We report 7Li NMR studies of V-substitution effects on spinel oxide superconductor LiTi2O4 (Tc = 13.4 K). In LiTi2-xVxO4 (x = 0-0.4), the V substitution for the Ti site suppressed the relative volume fraction of superconductivity faster than Tc. From the observation of fairly homogeneous enhancement in a 7Li nuclear spin-lattice relaxation rate, we conclude that the V substitution changes electron correlation effects through electron carrier doping from quarter electron filling 3d0.5 to 3d1.5 and then the antiferromagnetic correlation emerges. 
Y. Itoh, N. Moritsu and K. Yoshimura