Fractal Aspects of Lamellar Ferroelectric Domain Structures Formed under the Influence of Depolarization Fields in C_sH₂PO₄ and (NH₂CH₂COOH)₃· H₂SO₄

Abstract

Ferroelectric 180° domain structures of CsH₂PO₄ (CDP) and (NH₂CH₂COOH)₃· H₂SO₄ (TGS) have been observed in unelectroded b plates using the secondary emission mode of a scanning electron microscope (SEM). It is found that a lamellar domain structure is formed in CDP. The lamellar structure shows the fine periodicity along the normal to the walls nearly parallel either to the (100) plane or to the (801) plane. The periodic pattern corresponds to the first prefractal domain pattern that is characterized by the first prefractal of the pentad Cantor set. It is also revealed that the lamellar domain structure of TGS is observed to be the first prefractal domain pattern. The SEM observations establish that the prefractal domain patterns first dis-covered in KDP are common to the lamellar 180° domain structures which areformed in proper ferroelectrics under the influence of depolarization fields.CDP, TGS, ferroelectric domain, SEM, fractal, Cantor set, depolarization field, surface energy density