Polarization Reversal in MgO:LiNbO₃ Single Crystals Modified by Plasma-Source Ion Irradiation

Abstract

The polarization reversal has been studied by domain structure visualization and switching current recording in LiNbO₃ single crystals doped by 5% MgO irradiated by Ar⁺ ions. The abnormal domain structure evolution representing formation of charged domain walls has been revealed. It has been shown that low energy ion irradiation leads to increase of the bulk conductivity due to oxygen out-diffusion induced by radiative heating in vacuum. The inhomogeneous distribution of the electric field terminated the polarization reversal in high conductive layer. The analysis of the switching current data allowed revealing the input of the conductive current through charged domain walls.

Keywords:

• Lithium niobate
• nanodomains
• polarization reversal
• ion irradiation
• domain structure
• bulk conductivity
• domain engineering

Acknowledgments

The equipment of the Ural Center for Shared Use “Modern Nanotechnology”, Ural Federal University has been used. The authors acknowledge Pavel Zelenovskiy for imaging by Raman confocal microscopy and Maxim Neradovskiy for the PFM imaging. The research was made possible in part by RFBR (Grants 10-02-96042-r-Ural-а, 10-02-00627-а, and 11–02-91066-CNRS-а); by Ministry of Education and Science (Contract 16.552.11.7020), by OPTEC Co., by Ural Federal University development program (Grant №2.1.1.1/33).