Thermal and ferroelectric properties of potassium nitrate: polyvinyl fluoride composite films

The thermal and ferroelectric properties of potassium nitrate (KNO/sub 3/): polyvinyl fluoride (PVF) composite films have been studied. The dielectric constant has been measured as a function of temperature and shows a sharp change during heating and cooling cycles. Differential scanning calorimetry (DSC) has been employed to characterize the phase transitions and corresponding enthalpies in the composite. A good correlation has been found between the transition peak temperatures of the DSC and the transition temperatures of the dielectric measurements in the composite films. The DSC experiments suggest that phase III is retained at room temperature in the composite films. The switching current investigations support the presence of ferroelectric phase in the composite film. The capacitance-voltage (C-V) and conductance-voltage (G-V) characteristics of the composite films exhibit essential butterfly features of a ferroelectric material.