Magnification and scanning time dependence of secondary electron image contrast of ferroelectric domains in aged triglycine sulphate crystal

The influence of the incident electron dose on the secondary electron image (SEI) contrast of ferroelectric 180 degrees domains was investigated on a b plate of triglycine sulphate (TGS) without metallization. The TGS b plate aged at 20 degrees C was observed at 15 degrees C under various magnifications and scanning times while keeping an acceleration voltage of 0.7 kV and a current of 3 pA. We found that the SEI contrast between adjacent ends of domains diminished when the incident electron dose was larger than 0.5 mu C/cm(2) which is five times as large as the difference between spontaneous polarizations at 15 degrees C and 20 degrees C.