Thermal Depolarization in the High‐Temperature Ternary Piezoelectric System xPbTiO3–yBiScO3–zBi(Ni1/2Ti1/2)O3 |
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| Authors: | Troy Y. Ansell David P. Cann Eva Sapper Jürgen Rödel |
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| Affiliation: | 1. Materials Science, School of Mechanical, Industrial, and Manufacturing Engineering, Oregon State University, Corvallis, Oregon, Germany;2. Institute of Materials Science, Technische Universit?t Darmstadt, Darmstadt, Germany |
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| Abstract: | In the high‐temperature ternary perovskite piezoelectric system xPbTiO3–yBiScO3–zBi(Ni1/2,Ti1/2)O3 (PT–BS–BNiT), the addition of bismuth to the A site and nickel to the B site leads to compositions that exhibit diffuse relaxor‐like behavior. For these, depolarization temperature, not Curie point, is the critical value of temperature. Depolarization temperature (Td) is defined as the temperature at which the steepest loss in polarization occurs. This temperature is observed in poled materials through two different methods: loss tangent measurements and in situ d33. Across the ternary system, multiple dielectric anomalies occurred which was observed in dielectric tests where the dielectric peak broadens and becomes frequency dependent as BNiT content increased. For different compositions, the value of Td ranged between 275°C–375°C. Values for the piezoelectric coefficient increased with temperature up to d33 = 1000 pC/N during in situ d33. High temperature (up to 190°C) and high field (up to 40 kV/cm) were also applied to test ferroelectric properties in these regimes. |
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