Author(s)

Masanori Fukunaga, Masaki Takesada, Akira Onodera^*

Department of Physics, Hokkaido University, Sapporo, Japan.

The instability of thin ferroelectric films is discussed based on the close similarity of dielectric properties between bulk Bi-layered perovskites and thin BaTiO₃ films. The dielectric properties of pseudo-two-dimensional layered perovskites suggest that the bulk layered ferroelectric is a good model of ultra-thin ferroelectric film with a few perovskite units, free from any misfit lattice strain. It seems plausible that the ferroelectric interaction is still prominent but shows a crossover from ferroelectric to antiferroelectric along the unique c-axis (perpendicular to the film plane); with decreasing thickness, the ferroelectricity appears within the plane, which results in so-called “canted ferroelectricity”. An extra relaxation mode induced by surface effect of thin films correlates with soft mode, which results in a new intermediate phase between the paraelectric and ferroelectric phases. These evidences may indicate no critical thickness even for ferroelectric ultra- thin films.

Ferroelectricity, Layered Oxide, Perovskite, Thin Film, Size Effect

Fukunaga, M. , Takesada, M. and Onodera, A. (2016) Ferroelectricity in Layered Perovskites as a Model of Ultra-Thin Films. World Journal of Condensed Matter Physics, 6, 224-243. doi: 10.4236/wjcmp.2016.63022.