Effect of Oxygen Vacancies on the Motion of Domain Walls in BaTiO<sub>3</sub> Ceramics

The effect of in-situ vacuum and air high temperature annealing on the evolution of a mechanical loss peak in BaTiO3 ceramic is investigated. Vacuum annealing at high temperature suppresses the relaxation loss peak, and annealing in air at high temperature can restore the peak. This is interpreted as direct evidence of oxygen vacancies pinning the motion of domain walls.