BEHAVIOR OF PROUSTITE SINGLE CRYSTALS IN THE REGION OF LOW-TEMPERATURE PHASE TRANSITIONS.

An investigation was made of the behavior of the pyroelectric coefficient, permittivity, and resistivity of proustite (Ag//3AsS//3) single crystals in the temperature range 4. 2 to 300 degree K. It was found that the low-temperature phase transition at 30 degree K was of the first kind and that at 56 degree K was of the second kind. The pyroelectric coefficient of proustite measured at helium temperatures was 3 to 5 orders of magnitude higher than the pyroelectric coefficients of linear pyroelectrics and of ferroelectrics. Possible mechanisms responsible for the behavior of the spontaneous polarization at the phase transition points were considered. The transitions were accompanied by strong conductivity anomalies.