Ferroelectric domains in near-stoichiometric LiNbO_3 by e-beam polarization reversal

摘要

Local polarization reversal and periodical domain structure engineering by an electron beam in the Z-cut of near-stoichiometric LiNbO_3 crystal (NSLN) was investigated. The NSLN was grown from a congruent composition containing 6%wt. K_2O flux by top-seeded solution growth method. The 0.75 mm thick Z-cut samples were irradiated in the SEM with a lithography system. Both -z and +z crystal sides were studied after selective etching using an optical microscope. The sideways and frontal domain wall motions at different densities of introduced e-beam charges were analyzed. Irradiation conditions for long triangular string-like domain reversal in the crystal plates of 750 μm thickness were determined. The domain gratings were fabricated in the same crystal plates by e-beam. In the bulk crystal, domain gratings (λ = 10 μm) transformed to the 2D structure. The NSLN crystals hold promise for thick periodical domain structure engineering by e-beam technique.