Stability of the ferroelectric phase in polycrystalline KNO3 investigated by photoacoustic and calorimetric techniques

The successive phase transitions in a polycrystalline KNO3 sample have been studied using photacoustic and calorimetric techniques. The measured temperature dependence of the photoacoustic amplitude carries signatures of the transitions undergone by the sample. The results indicate that the intermediate ferroelectric phase in KNO3 is only a metastable one. This raises doubts regarding its applicability in fabricating ferroelectric memory devices.