Conduction-electron spin relaxation and diffusion in the radical cation salt diperylene hexafluorophosphate

Single crystals of the quasi-one-dimensional organic conductor (PE${)}_2$ ${\mathrm{PF}}_6$⋅2/3THF (PE: perylene, THF: tetrahydrofurane) were studied by pulsed-electron spin resonance (ESR) at Larmor frequencies of ν = 300 MHz and 10 GHz in the metallic high-temperature phase (T≳100 K). Anisotropy and temperature dependence of conduction-electron spin-lattice and spin-spin relaxation were derived. The anisotropy of the diffusion constant exceeds a factor of 800. Quasimicroscopic restriction of the spin diffusion was analyzed by static-gradient spin-echo ESR, indicating characteristic chain lengths of ∼90 μm. A conclusive picture of charge and spin dynamics of this molecule-based metal can thus be derived. © 1996 The American Physical Society.