Leakage mechanisms of double-perovskite Bi2FeMnO6 epitaxial thin films

Abstract

Multiferroic Bi2FeMnO6 epitaxial thin films were deposited on conductive SrRuO3/SrTiO3 (0 0 1) substrate by pulse laser deposition. The Au/Bi2FeMnO6/SrRuO3 capacitor structure was used to investigate the electrical property. Bi2FeMnO6 thin film has a good ferroelectric retention and the downward polarization state. For Bi2FeMnO6 film, different leakage mechanisms play a predominant role under different electric field regions. Ohmic conduction works under 80 kV cm−1. From 80 to 1350 kV cm−1, the leakage mechanism depends on the electric field polarity and Poole–Frenkel emission is the dominant mechanism at negative bias. Schottky emission dominates the leakage current above 1350 kV cm−1. The extracted zero-field ionization energy for Poole–Frenkel emission is ~0.4 eV. A schematic energy band alignment of Au/Bi2FeMnO6/SrRuO3 capacitor was constructed to describe the contribution of Schottky emission.