Polarization and hysteresis in low resistivity ferroelectric composites

A compensating technique suitable for measuring the polarization and hysteresis in ferroelectric materials with low resistivity is reported. In this method, three different poling voltages waveforms are successively applied to a sample while the current i, is measured. These are: a sinusoidal, a positively rectified and a negatively rectified sinusoidal voltages. The polarization hysteresis loop is then computed through the integration of the difference between the current obtained during the full sinusoidal voltage loop (i.e. i_t) and the sum of the other two currents (i⁺ + i^-. In this paper we use this method to determine the remanent polarization and coercive field in a ferroelectric composite of calcium modified lead titanate (PTCa), of a low resistivity formulation, and a copolymer of polyvinylidene fluoride (i.e. P(VDF/TrFE)) as a function of the temperature and field.