Observation of shocked and unshocked BaZnGeO 4 by means of electron microscopy

Abstract

Electron microscopic observations were performed on shocked and unshocked BaZnGeO 4 (BZG). Particular attention was given to the superlattice relation. A specimen shocked to the pressure range of 19–27 GPa, showed a small distortion from the original hexagonal lattice, to an orthorhombic symmetry. Along with this distortion, weak superlattice reflections along the c∗ direction in the unshocked BZG were found to disappear completely, while the repetition mode of superlattice reflections along the b∗ direction ([110]∗ direction in the hexagonal structure) as found to change from three to six, and then to four, with increasing shock pressure. A single crystal—single crystal transition, on a submicrometer scale, was shown to occur due to a small displacement of atoms during shock process.