Ageing of TGS crystals

Virgin TGS crystals, observed by SEM and TEM replicae, show many polygonal inclusions with different electric behaviour which corresponds to a non-ferroelectric phase. Such inclusions would explain the delay-time effect, the existing residual domains and the wide range of permitivity values, in the phase transition, measured by different investigators. SEM observations of switching fatigued and thermally fatigued samples demonstrate a strong secondary emission contrast which is due to an increase in its conductivity. In the electrically-aged samples the surface layers are altered, but no ion diffusion from the electrode has been observed through EDAX. However, in thermally-aged samples such diffusion is observed. Carbon replicae TEM observation shows a polygonal form matrix which must be due to TGS-C crystals. These results allow one to interpret the ageing process origin and development in both cases, electrically and thermally fatigued crystals, and also the phase transition in partially-aged samples.