Polarised-Light and Electron Microscopy of the Static Domain Structure of Ferroic Mn3B7O13Br Boracite at Room Temperature

The static domain structure of ferroic Mn3B7O13Br, abbreviated in what follows as Mn-Br, synthetic boracite crystals have been analysed by polarized-light microscopy (PLM) and by field emission scanning electron microscopy (FE-SEM) at room temperature. As most boracites, Mn-Br possess dielectric, elastic, magnetic and optical properties of unusual interest. The stable phase of Mn-Br at room temperature has orthorhombic symmetry (point group mm2) which transforms to a cubic phase (space group ) when heating the crystal above 540 K. Optical examination of all samples grown by chemical transport reactions showed a bulky domain configuration which was resolved in a fine lamellar configuration under the electron microscope.