Direct observation of asymmetric domain wall motion in a ferroelectric capacitor

• Published in: Acta materialia 2013-10, Vol.61 (18), p.6765-6777
• Main Authors: Lee, Ja Kyung, Shin, Ga Young, Song, Kyung, Choi, Woo Seok, Shin, Yoon Ah, Park, Seong Yong, Britson, Jason, Cao, Ye, Chen, Long-Qing, Lee, Ho Nyung, Oh, Sang Ho
• Format: Article
• Language: English
• Subjects: 90° Domains; Applied sciences; Cross-disciplinary physics: materials science; rheology; Depolarization field; Exact sciences and technology; Ferroelectric thin film; In situ transmission electron microscopy; Materials science; Metals. Metallurgy; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Polarization switching
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2013.07.051

We report in situ transmission electron microscopy observations of the 180° polarization switching process of a PbZr0.2Ti0.8O3 (PZT) capacitor. The preferential, but asymmetric, nucleation and forward growth of switched c-domains were observed at the PZT/electrode interfaces, arising due to the built-in electric field induced at each interface. The subsequent sideways growth of the switched domains was inhibited by the depolarization field due to the imperfect charge compensation at the counter-electrode and also at the boundaries with preexisting a-domains, which contributed further to the asymmetric switching behavior. It was found that the preexisting a-domains split into fine a- and c-domains constituting a 90° stripe domain pattern during the 180° polarization switching process, revealing that these domains also actively participated in the out-of-plane polarization switching. The real-time observations uncovered the origin of the switching asymmetry and further clarified the importance of charged domain walls and the interfaces with electrodes in the ferroelectric switching processes.