Domain-wall conduction in AFM-written domain patterns in ion-sliced LiNbO3 films

Abstract

We report on the static conduction at domain walls (DWs) in stable domain gratings written by dc-AFM-tip voltages in thin (300–500–nm–thick) ion-sliced LiNbO3 films embedded to SiO2/LiNbO3 substrates. Steady currents were found at DWs by conductive atomic force microscopy. The currents at DWs are larger than those in switched and unswitched domains not less than by five orders of magnitude. The current–voltage characteristics at DWs differ fundamentally from the I-U curves in switched domains. Piezoelectric hysteresis loops Hf(Utip) measured over written gratings indicate that a contribution from the domain motion to the currents at DWs can be neglected. The scope of data obtained permits us to relate these currents unambiguously to the domain-wall conduction (DWC). DWC persists during observation times of about several months, i.e., its steadiness is determined by the stability of written domains.