The use of electron spin echo spectroscopy to study the ferroelectric phase transition in ammonium sulfate

Using the SO radical generated by γ-irradiation as the paramagnetic probe electron spin echo modulation analysis techniques are used to study the phase transition in ammonium sulfate. A drastic reduction in the phase memory time TM, from 2.2 μs at room temperature to 0.5 μs at 77 K is observed. By analyzing the deuterium modulations in terms of a multishell model such a decrease in Tm is attributed to a movement of the ammonium protons closer to the sulfate group in the low temperature phase.