Analysis of the thermal hysteresis in partially deuterated tryglicine selenate

Dielectric constant data on partially deuterated triglycine selenate (TGSe) (1-x)(DTGSe)(x) for x = 0, 0.35 0.80 show a steady increase of thermal hyst eresis Delta T(x) with deuteration, in agreement with previous data by Gesi . In this work we correlate this observed thermal hysteresis with the param eter g(x) = (gamma/beta)N(2)mu(2) obtained from hysteresis loops data, in o rder to characterize the ferroelectric transition. For x = 0, the transitio n is close to a tricritical point (g congruent to 1/3) and we see that cool ing very slowly through T-C under these quasitricritical conditions results in a very large residual contribution to the dielectric constant at the fe rroelectric phase.