Leakage current behavior in lead-free ferroelectric (K, Na)NbO3-LiTaO3-LiSbO3 thin films

Conduction mechanisms in epitaxial (001)-oriented pure and 1 mol % Mn-doped (K-0.44, Na-0.52, Li-0.04) (Nb-0.84, Ta-0.1, Sb-0.06)O-3 (KNN-LT-LS) thin films on SrTiO3 substrate were investigated. Temperature dependence of leakage current density was measured as a function of applied electric field in the range of 200-380 K. It was shown that the different transport mechanisms dominate in pure and Mn-doped thin films. In pure (KNN-LT-LS) thin films, Poole-Frenkel emission was found to be responsible for the leakage, while Schottky emission was the dominant mechanism in Mn-doped thin films at higher electric fields. This is a remarkable yet clear indication of effect of 1 mol % Mn on the resistive behavior of such thin films. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3531575]