Non-linear dielectric properties of aluminium/monomolecular layers of calcium behenate/aluminium structures

Abstract

We studied the non-linear dielectric properties of aluminium/monomolecular layers of calcium behenate/aluminium structures at high electric induction ( D > 10 −3 C m −2). These properties generally arise from the motion of electric charges that are trapped in both the alumina at the surface of the electrodes and in the monolayers and result in a hyperpolarizability. However, in some particular cases in which dipolar relaxation mechanisms were present we observed a decrease in the polarizability. This decrease is due to a Langevin-Debye-type saturation at high electric field. Since the mechanical compressibility of the monomolecular layers is small (1.6 × 10 −10 N m −2), electrostatic compressibility and the electrostriction phenomena are of minor importance. The introduction of small quantities of water produces a marked increase in the non-linear phenomena which may mask all the other phenomena.