Electron-spin-echo experiments on the one-dimensional conductor[(fluoranthene)2]+[(PF6)x(SbF6)1−x]− (x≈0.5)

The electron-spin-echo decay function was determined for the conducting phase of ${\left[{\left({\mathrm{C}}_{16}{\mathrm{H}}_{10}\right)}_2\right]}^{+}{X}^{-}$ in the temperature range 183-300 K. The decay function exhibited an $\exp [-{\left(\gamma t\right)}^{\frac{3}{2}}]$ dependence, characteristic of one-dimensional spin diffusion. The ratio $5\times {10}^6\le \frac{D_{\parallel }}{D_{\perp }}\le 5\times {10}^8$ for the inner-stack—to—out-of-stack diffusion rates was determined from the characteristic time $t_0$, at which the electron-spin-echo decay function changed to the "conventional" $\exp (-2\mathrm{}{\gamma }^{\prime }\tau )$) form. The deduced value $2\times {10}^{13}\le D_{\parallel }\le 2\times {10}^{16}$ rad/s is consistent with the bulk dc conductivity and with recently determined nuclear spin-lattice relaxation rates. The overall assumption of highly mobile electronic spins was confirmed by an Overhauser-type experiment.