Influence of temperature variations on the visualisation of the ferroelectric domains of TGS and TAAP crystals by scanning electron microscopy

Temperature variations of aged Triglycine Sulphate (TGS) and Telluric Acid Ammonium Phosphate (TAAP) samples increase the contrast between positive and negative ends of domains observed with a scanning electron microscope. For freshly cleaved surface of TGS, an increase of temperature of 2°C inverts the contrast between these domains. When the temperature of the TGS samples increases continuously, we observe a deformation of the picture on the screen, but it is not observed for TAAP samples. Thermally stimulated electron emission is also observed and measured. These phenomena are due to the surface charges produced by the modification of the spontaneous electric polarization of the samples when the temperature varies.