Recently, a work from the group of Prof. Faxin Li and Prof. Daining Fang of the College of Engineering is selected as the Cover Featured Article on the latest issue of Applied Physics Letter (http://scitation.aip.org/content/aip/journal/apl/103/23). The title is “90-degree polarization switching in BaTiO3 crystals without domain wall motion”. The first author is Mr. Yingwei Li, a Grade 2010 Ph.D. student from College of Engineering.

For a long time in the field of ferroelectrics, there is a paradox called Landauer’s paradox: The coercive field based on the theory of Landua - Devenshire is always two or three orders larger than the experimental value. The cause is that in theory, domain switching is a temporal process and is also called intrinsic domain switching. While in experiments, domain switching is always accompanied by domain nucleation, domain wall movements. In recent years, researchers have tried to realize 1800 intrinsic domain switching in ultrathin films by suppressing domain nucleation, but these efforts never succeed.

Fig.1 The interlocking domains in BaTiO3 crystals via compression depolarization

The group of Prof. Faxin Li and Prof. Daining Fang proposed a special idea. They fabricated interlocking 90-degree domain patterns in large bulk BaTiO3 crystals via compression depolarization. By suppressing the motion of 90-degree domain wall via the strain constraint, they for the first time realized polarization switching without domain wall motion. The measured coercive field is much larger than that of conventional switching via domain wall movement, and is very close to the theoretical value. Thus the observed domain-wall free switching can also be called quasi-intrinsic domain switching.  

This work had been appreciated by Prof. James Scott of Cambridge University, “the father of integrated ferroelectrics”. He agreed to act as the coauthor and help review the related history in the Introduction part. This paper has been recommended by the reviewer to be published quickly without further revisions.