Neutral-ionic phase separation and one-dimensional ferroelectricity in organic relaxors

Microscopic phase segregation by chemical doping and resultant anomalous dielectric response have been investigated for tetrathiafulvalene-p-chloranil complex doped with trichloro-p-benzoquinone ( QCl3). Beyond a critical QCl3 content, the system shows a behavior of relaxor ferroelectrics, as characterized by strong frequency dispersion and a rounded peak shape of gigantic dielectric susceptibility. The relaxor phase arises from one-dimensional ferroelectricity, as evidenced by a diffuse x-ray scattering, in which interchain ferroelectric coupling associated with neutral-ionic transition is interrupted by impurity-generated neutral microclusters.