Cloverleaf domain patterns in multiferroic RMnO$_{3}$ (R = Ho, Er, and Lu)

Hexagonal RMnO$_{3}$ (R=rare earths) exhibits a unique improper ferroelectricity induced by structural trimerization. Intriguing domain pattern associated with ferroelectricity and trimerization, so-called ``cloverleaf'' domain pattern, has been reported in YMnO$_{3}$ [1] In this talk, we will report the domain structures in a series of RMnO$_{3}$ with different rare earth elements, obtained from the results of our transmission electron microscopy. Characteristic cloverleaf domain patterns are clearly observed in RMnO$_{3}$ (R = Ho, Er, and Lu). The results imply that the cloverleaf domain pattern is a common domain feature in the hexagonal manganites. \\[4pt] [1] T. Choi et al., Nature Materials 9, 818 (2010)