Temperature Dependence of the Spontaneous Polarization and the Dielectric Susceptibility near the Phase Transitions in Ammonium Sulfate

Abstract

Spontaneous polarization and the dielectric susceptibility are calculated as a function of temperature close to the paraelectric-ferroelectric phase transition (7" c =223 K) in (NH 4 ) 2 S0 4 . This calculation is performed using a mean field model by fitting the expressions derived for the dielectric susceptibility to the experimental data for the dielectric constant at the fixed frequencies of 100, 500 and 2000 Hz in ammonium sulfate.Our calculations show that an observed first order transition can be described adequately by the mean field model given here for ammonium sulfate.

Temperature Dependence of the Spontaneous Polarization Near the Ferroelectric-Paraelectric Transition in NaNO2

“…This model has already been considered for the ferroelectric-paraelectric transition in ammonium sulfate [30]. F a a P a P a P (9) at a constant volume V, where a 2 and a 4 are the temperature-dependent terms, a 0 and a 6 are constants.…”