Time-dependent conduction current in lithium niobate crystals with charged domain walls

We present the experimental study of the increase and decrease of the abnormal conduction current appeared during polarization reversal at elevated temperatures (120–250 °C) in stoichiometric and MgO doped lithium niobate single crystals. It is shown that the conduction current is caused by existence of the through charged domain walls. The time dependence of the conduction current has been measured in low electric field immediately after partial switching. The maximal value of the conduction current in crystal with through charged domain walls is of 4–5 orders of magnitude higher than in initial single domain state. The activation energy is 1.1 eV.