NMR Studies for Spinel Phase Li_xZn_1−xV₂O₄ System

抄録

The mechanism of magnetic and transport properties of the spinel phase Li_xZn_1−xV₂O₄ system was studied by using NMR technique. On the basis of ⁵¹V NMR, it was found that metallic-magnetic state of LiV₂O₄ and nonmetallic-nonmagnetic state of ZnV₂O₄ coexist in Li_xZn_1−xV₂O₄ system. The X-dependence of the ratio between metallic-magnetic state and nonmagnetic state was determined and its origin was discussed. The ⁷Li NMR shift measurement suggested that there existed the preference of valency of vanadium ions depending on the nearest neighbor configuration of Li⁺ ions or Zn²⁺ ions. The metal-insulator transition of this system was understood in terms of the percolation effect of the metallic-magnetic vanadium ions.