Dielectric relaxation in NH4HSO4 above room temperature

The dispersion curves of the dielectric response of NH4HSO4 show that the corrected imaginary part of permittivity, εʺ, and its real part ε′ versus frequency reveal a dielectric relaxation around 9.1 × 105 Hz at 31 °C, which shifts to higher frequencies (∼ 106 Hz) as the temperatures increases. The relaxation frequency shows an activated relaxation process over the temperature range 31–83 °C with activation energy Ea = 0.14 eV, which is close to that derived from the dc conductivity. We suggest that the observed dielectric relaxation could be produced by the H+ jump and SO4− reorientation that cause distortion and change the local lattice polarizability inducing dipoles like HSO4−.