Proprietes electriques du chlorure d'argent monocristallin et charge d'espace

Abstract

Very high dielectric permittivity and polarisation in AgCl crystals are observed in d.c. and very low frequencies (from 10 −4 Hz to 100 KHz) with different electrodes (silver painting and solid chrome). The potential distribution is also studied with vibrating wire method. Near 100°C and for frequencies below 1 Hz, non-linear phenomenon appear for a.c. voltages greater than 0,1 V. When a.d.c. voltage is superposed, we observe three kinds of behaviour: for low voltages and low frequencies, adsorption predominates; for some volts, space charge appears and beyond surface states produce high permittivity. Shape of potential distribution and dielectric permittivity can be explained by space charge polarisation, adsorption of Ag + ions at the electrodes and filling of surface states.