Hydrogen-induced degradation in multiferroic BiFeO3 ceramics

Chemical stability of multiferroic BiFeO3 (BFO) ceramics has been studied through electrochemical hydrogen charging, in which BFO ceramic pellets were placed in 0.01 M NaOH solution with hydrogen deposited on their electrodes from the electrolysis of water. The properties of the samples were greatly degraded after the treatment: The leakage current was increased by orders of magnitude, the capacitance and the dielectric loss were dramatically increased in low frequency region. It was proposed that hydrogen entered into BFO lattice and existed at interstitial sites and the degradation was explained by hydrogen's reduction of some Fe3+ to Fe2+ in BFO. Hydrogen-induced degradation occurs relatively easily in BFO and much attention should be paid to it for BFO-based devices. (C) 2007 Elsevier B.V. All rights reserved.