Thermally stimulated depolarisation currents in stearic acid multilayers

Abstract

Measurements are reported of thermally stimulated depolarisation (t.s.d.) currents on stearic acid multilayers prepared by the Langmuir–Blodgett technique and fitted with aluminium electrodes. The effect of u.v. irradiation is also reported and the results are discussed in the light of the dependence of the dielectric loss on frequency and on temperature, showing wide departures from the classical Debye spectra. It is concluded that the principal t.s.d. current peak is due to the movement of hopping charges in the material and evidence is obtained for the presence of a structural phase transition at around 250 K, above which the charge movements suddenly become possible. The general significance of these measurements for the interpretation of t.s.d. data is explained.