Abstract-Visualization of ferroelectric domains in a hydrogen-bonded molecular crystal using emission of terahertz radiation

M. Sotome¹, N. Kida^1,a), S. Horiuchi^2,3 and H. Okamoto¹


1 Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwa-no-ha, Chiba 277-8561, Japan
2 National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8562, Japan
3 CREST, Japan Science and Technology Agency (JST), Tokyo 102-0076, Japan
a) E-mail: kida@k.u-tokyo.ac.jp
Appl. Phys. Lett. 105, 041101 (2014); http://dx.doi.org/10.1063/1.4890939
http://scitation.aip.org/content/aip/journal/apl/105/4/10.1063/1.4890939

Using a terahertz-radiation imaging, visualizations of ferroelectric domains were made in a room-temperature organic ferroelectric, croconic acid. In as-grown crystals, observed are ferroelectricdomains with sizes larger than 50-μm square, which are separated by both 180° and tail-to-taildomain walls (DWs). By applying an electric field along c axis (the polarization direction), a pair of 180° DWs is generated and an each 180° DW oppositely propagates along a axis, resulting in a single domain. By cyclic applications of electric fields, a pair of 180° DWs repeatedly emerges, while no tail-to-tail DWs appear. We discuss the usefulness of the terahertz-radiation imaging as well as the observed unique DW dynamics.