Degradation of the electrical conductivity of the charged domain wall in reduced lithium niobate

Abstract

In the present work, we investigated the effect of prolonged exposure on the electrical conductivity of crystals with a charged domain wall (CDW) in congruent lithium niobate crystals (LiNbO3, LN) of a nonpolar x-cut. Bidomain ferroelectric structures containing charged head-to-head domain boundaries were formed in the samples using methods of diffusion annealing in the air near the Curie temperature and infrared annealing in an oxygen-free environment. Reduction annealing of crystals in a nitrogen atmosphere was carried out to form color centers and concomitant increase in conductivity. Using an atomic force microscope (AFM) we observed the effect of degradation of the current value recorded when measuring the I-V curve. The influence of storage conditions on the electrical conductivity of CDW was studied. It was found that this effect was not related to the influence of the surrounding atmosphere on the surface but was presumably related to the redistribution of charge carriers shielding the bound charge of the CDW.