High temperature dielectric anomaly of ammonium sulfate [(NH4)(2)SO4] crystal

Abstract

Dielectric anomalies were observed in ammonium sulfate [(NH4)(2)SO4] crystals at T-0 similar or equal to 413 K after the crystal was heated above 413 K. Frequency dependence of dielectric loss across T-0 similar or equal to 413 K observed in the 2nd heating-up cycle could be best fitted by two overlapping relaxation functions of the Cole-Cole type. The fast component in higher frequency region depicts a sharp discontinuity of relaxation frequency at T-0 similar or equal to 413 K while the slow component in lower frequency region shows a continuous slowing down to zero relaxation frequency as temperature increased to T-0 similar or equal to 413 K.