Dielectric Properties of Solid Solutions of Sodium Niobate‐Lead Zirconate and Sodium Niobate‐Lead Titanate

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Abstract
Solid solutions based on sodium niobate with limited amounts of lead and zirconium or lead and titanium solute ions have been investigated with respect to their dielectric constant versus temperature at 1 kc. per second from −175° to 300°C. Lead zirconate additions to sodium niobate up to 15 mole % cause an increase in dielectric constant, with a value of 1345 at 6°C. being the maximum recorded. Lead titanate additions to sodium niobate cause a general increase in dielectric constant up to 25 mole %, with 675 at 30°C. and 4670 at 154°C. being the maximum values recorded. Polarization versus applied field measurements up to 30,000 volts per cm. show nonreversible polarity for the lead zirconate compositions, whereas the compositions containing from 10 to 50 mole lead titanate are ferroelectric. An induced ferroelectricity phenomenon occurs for the composition containing 5 mole % lead titanate. A remanent polarization of 15 microcoulombs per sq. cm. at a coercive force of 7800 volts per cm. was obtained at room temperature for the composition 0.85 NaNbO3–0.15 PbTiO3.