Acoustic emission upon spontaneous polarization in triglycine sulfate single crystals

We report on the results of analysis of acoustic emission (AE) under thermal action on a triglycine sulfate (NH$_{2}$CH2COOH)$_{3}$ $\cdot$ H$_{2}$SO$_{4}$ crystal. The triglycine sulfate single crystals grown from solution and not subjected to mechanical treatment are heated to a temperature above the Curie point ($T_C$ = 49$^\circ$C). During natural cooling of the crystal, a transition from the paraelectric to ferroelectric phase is accompanied by intense AE. In the temperature range $\sim$28–30$^\circ$C, an anomalous drop of the mean-square voltage in the AE signal is observed against the background of monotonic accumulation of AE events.