Preparation and some dielectric properties of deuterated triglycine selenate

Deuteration effect on tricritical phase transition of triglycine selenate: Calorimetric and dielectric measurements analyzed in the framework of Landau theory

“…5. 2,30 On the contrary, data of the nondeuterated sample ͑x =0͒ exhibits lack of repeatability in the paralectric phase when the sample is cooled and heated successively ͑see Fig. Transition temperature and hysteresis increases with deuteration, while, on the contrary, peak value decreases.…”

“…[1][2][3][4][5][6][7] As a paradigm of this behavior, triglycine selenate ͑NH 2 CH 2 COOH͒ 3 H 2 SeO 4 , hereafter TGSe, is a well known uniaxial, ferroelectric material belonging to the triglycine sulfate ͑TGS͒ family, which exhibits an order-disorder phase transition 8,9 ͑from high temperature space group P2 1 / m to low temperature space group P2 1 ͒ at T = 295 K. These crystals have applications as infrared detectors and vidicons. Their influence is greatly significant if the phase transition happens to be close enough to a tricritical point ͑TCP͒, where the first or second order nature of the phase transition can be modified by such a change.…”