Influence of radiation-induced effects on electric and dielectric properties of ferrocene

The dielectric permittivity (ϵ) and dielectric losses (tan δ) of ferrocene crystallites are measured with different frequencies in the temperature range 140-375 K. The results confirm the existence of the phase transition at 163.9 K in addition to anomalous behaviour while heating indicating the presence of a metastable structure in the temperature range 250-290 K. The d.c. electrical conductivity (σ) is measured in heating-cooling cycles between 120 and 300 K. The behaviour while cooling is completely different from that while heating and the phase transition becomes less pronounced in the second cooling-heating cycle. The σ-T relationship reveals an activation energy of conduction of 0.89 eV in the high temperature range while cooling. The effect of irradiating samples of ferrocene with γ-rays in different doses on both the dielectric permittivity and the electrical conductivity is also discussed. The current density (J) is measured as a function of the applied electric field (E) at three different temperatures; below the phase transition point, at room temperature and at 345 K in order to estimate the type of conduction dominates and the effect of E upon the conductivity measurements of this material. The effect of γ-irradiation with different doses on the J-E characteristics of ferrocene is also considered.