Dielectric relaxation in pure and irradiated TGSP crystals

Low frequency dielectric measurements in triglycine sulpho-phosphate (TGSP) and gamma-irradiated TGSP crystals were carried out around the ferroelectr ic to paraelectric phase transition. The dispersion found in the ferroelect ric phase cannot be explained only by a Debye equation with a single relaxa tion time. The ratio of the Curie constants in the para- and ferroelectric phase (C-p/C-f) for the irradiated TGSP samples show that the crystal is pa rtially clamped. The deviations from the typical single relaxation behaviou r are more pronounced in irradiated samples clearly indicating the contribu tion of defects in addition to the impurities to the dynamics of the system . (C) 2000 Elsevier Science B.V. AU rights reserved.