Effects of electrostatic field on the diffraction contrast of imperfections in quartz

AT-cut oscillator plates were examined by X-ray diffraction topography under an applied electrostatic field of more than 5 kV/mm. Growth layers, cellular structures and some misfit boundaries, which are hardly observable without the field, can be detected with remarkable contrast. After the field has been switched off, the effects decrease with a relaxation time of about 10 h. Not only the converse piezo-electric effect due to an instantaneous field, but also ionic or electronic charges account for the contrast change. The present technique is useful for studying crystal imperfections.