ELECTRICAL AND OPTICAL-PROPERTIES OF RELAXOR FERROELECTRICS

The dielectric and optic/electro-optic properties of hot-pressed ceramics of composition (l-x)(Pb1-y - Lay)(Mg1/3Nb2/3)O3 - xPbTiO3 (y = 0.01) have been investigated. The materials exhibit high peak dielectric constants (>20000) with typical relaxor ferroelectric behavior. The ceramics are adequately transparent for optical and electro-optical evaluation with transmission better than 50% at 600 nm. High refractive indices are observed (>2.5 at 632.8 nm) and the dispersion of the refractive index is well described by a single-term Sellmeier equation. The temperature dependence of the refractive index exhibits a linear region above 390°C and a polarization induced decrease of the index via the electrooptic effect below this temperature. The transverse quadratic electro-optic coefficients, (R11-R12) and (g11-g12), were evaluated both as a function of temperature and frequency. Electro-optic switching experiments indicate rapid response of less than 1 μsec, suitable for transverse shutter mode operation. © 1990, Taylor & Francis Group, LLC. All rights reserved.