Electron Spin Dynamics in (DMe-DCNQI)₂M (M = Li_1-x Cu _x (x < 0.14), Ag)

The quarter-filled π band systems, (DMe-DCNQI)_2M(M=Li_1-x Cu _x (x ≤ 0.14), Ag) were systematically studied with electron paramagnetic resonance (EPR). The intercolumn spin hopping rate $D_\bot$ in Li_1-x Cu _x -salt was obtained from the EPR linewidth. The temperature dependence of $D_\bot$ can be understood with the hole soliton model which also explains the DC conductivity. The π−d mixing of the Cu-salt enhances both $D_\bot$ and $\sigma_\bot$ by 10³ times more than the Li-salt, which is consistent with the fact that the only Cu-salt has three-dimensional Fermi surface, but that Ag-salt is one-dimensional in spite of the mixing enhancement of $D_\bot$ by 10 times more than the Li-salt.