Local mapping of spin diffusion at the Peierls transition in (FA)2PF6 with ESR imaging

Pulsed ESR is used for microscopic imaging of the conduction electron spin dynamics in the organic crystal (FA)2PF6. Previous conductivity and X-ray measurements of this crystal show a Peierls transition at 180 K. The `localʹ diffusion measurements reveal that the spins diffuse freely far from the crystal boundaries. This enables the extraction of the free diffusion coefficient by a one-parametric fit. The temperature dependence of the diffusion coefficient was found to correlate with a previously reported structural transition occurring well above the Peierls transition.