Dielectric and Electrostrictive Anomalies Slightly above the Curie Point of NaNO2

Abstract

The temperature dependence of the dielectric constant of NaNO 2 was investigated in detail in the neighbourhood of the Curie point. A new peak was found in the E 22 – T curve at about 1°C above the Curie point (162.1°C). The peak at the Curie point was shifted to higher temperature by application of a D.C. bias field. At the bias field of 3kV/cm, only one sharp peak was observed at 163.2°C. The piezoelectric constants were measured by resonance method under various D.C. bias fields, from which the electrostrictive constants were calculated. The electrostrictive constants show complicated temperature dependence in the narrow temperature range above the Curie point. The observed dielectric and electrostrictive anomalies should correspond to the antiferroelectric-paraelectric phase transition which has been clarified by X-ray and specific heat measurements by Yamada, Shibuya and Hoshino. From the fact that the second peak of E 22 does not show temperature hysteresis, the transition should be of the second or...