Separation of Pyroelectric Currents and Thermally Stimulated Currents in Poly

Pyroelectric currents and thermally stimulated currents in polyvinylidene fluoride) polymer (PVF2) were studied. PVF2 samples were oriented with high electric fields and then were heated at a constant rate. On the first thermal cycle the current was large and irreversible, a characteristic of thermally stimulated current. On the second and subsequent thermal cycles, the current was reversible and reproducible, a characteristic of pyroelectric current. Several experiments were performed to determine the fraction of pyroelectricity present in the first thermal cycle. The experimental results indicate that the first thermal cycle contains up to about 50% more pyroelectricity than the second and subsequent cycles. Measurements made with the sinusoidal temperature technique indicate that most of the first thermal cycle current is nonpyroelectric.