Migration and redistribution of oxygen vacancy in barium titanate ceramics

Degradation of barium titanate based multilayer capacitor mainly results from migration and redistribution of oxygen vacancy. For barium titanate ceramics, the authors observe an internal friction relaxation peak around 70 degrees C due to oxygen vacancy, and its relaxation strength differs greatly for specimen aged at 85 degrees C for 120 h and at 150 degrees C for 5 h. Two possible explanations are proposed, one based on symmetry-conforming short-range order while the other on the interaction between oxygen vacancy and domain wall during aging process. In any case, relaxation thermodynamics is a powerful tool to investigate the migration and redistribution of oxygen vacancy in barium titanate ceramics. (c) 2006 American Institute of Physics.