  Charge ordering, dielectric permittivity and local structure of
La5/3Sr1/3NiO4 system have been explored X-ray charge scattering, complex
dielectric impedance spectroscopy, and extended X-ray absorption fine structure
(EXAFS) measurements, made on the same single crystal sample. The local
structure measured by the temperature dependent polarized Ni K-edge EXAFS shows
significant distortions in the NiO2 planes. These local distortions could be
reasonable cause of high dielectric permittivity of the title system (e=100 at
5K) with the charge ordering in this system being a ferroelectric-like second
order transition.
