Polarized-light and electron microscopy study of the static domain structure of ferroic Fe3B7O13I boracite at room temperature.

The static domain structure of ferroic Fe3B7O13I, (abbreviated as Fe-I) synthetic boracite crystals has been analyzed by polarized-light microscopy (PLM) and by field emission scanning electron microscopy (FE-SEM) at room temperature. As for most boracites, Fe-I shows dielectric, elastic, magnetic and optical properties of unusual interest. Upon cooling, Fe-I boracite shows a sequence of structural phase transitions from the cubic -43m to the orthorhombic mm2 (Tc = 348K), the monoclinic m (Tc = 218 K) and the trigonal 3m phases (Tc = 191 K). At room temperature, the Fe-I crystals present an orthorhombic domain structure which consists of six ferroic domains. Our results show that both techniques: PLM and FE-SEM are complementary for the visualization of ferroic domains. [ABSTRACT FROM AUTHOR]