부산대학교 도서관

Measurements of the charge released (ΔQ > 0) by crystalline samples of ferroelectric NaNO2 at low temperatures show a temperature dependence of type Q/A = aTa + bT4 + ce-θ/T. The first term is weak and ill defined in the temperature range examined. The other two terms are very well established experimentally. The second (negative) term can be associated with the secondary pyroelectric coefficient, and the third one (positive) is analogous to exponential terms observed in various other ferroelectrics at low T, which are interpretable as due to low lying optical modes. A change in sign of the total pyroelectric coefficient, similar to that observed in KDP and other materials, is observed at 40 K.