Effect of depolarization and coercivity on actuation strains due to domain switching in barium titanate

Large electrostrictive actuation in ferroelectric single crystals can be achieved through non-180 degrees domain switching using various biasing fields and loads. The theoretical maximum actuation strain such as 1.1% for barium titanate crystals, however, has not been observed yet. In this letter, the authors propose a possible mechanism accounting for the depolarization effect to explain the significant strain reduction observed in their recent experiment. They find that a low-energy path requires the switching of 90 degrees domains together with that of in-plane alternating layers of 180 degrees domains formed to reduce the depolarization energy. Therefore, reduction in strain is significant for crystals with large 180 degrees coercivities. The result is consistent with their recent experimental observations. (c) 2007 American Institute of Physics.