Reversible pyroelectric effect in Pb(Sc_1/2Ta_1/2)0₃ ceramics under DC bias

Abstract

It has been shown that quenched Pb(Sc_l/2Ta_1/2)0₃ (PST) disordered ceramics and crystals show diffuse dispersive dielectric properties, while well annealed ordered materials exhibit normal sharp first order transition. The pyroelectric depolarization measurements taken using a Hewlett Packard Model 4140B picoammeter/DC Source under computer controlled heating cycle also have shown different behaviors between disordered and ordered materials

In this work pyroelectric measurements by Chynoweth method under DC bias up to 1.8 KV/mm within a temperature range of 70°C around the temperature of maximum dielectric constant have been studied. A very significant enhancement of the pyroelectric signal under DC bias is observed in thermally quenched disordered samples. The largest enhancement of the signal appears at temperatures some degrees below the temperature of maximum dielectric constant

The existence of microdomains in disordered materials is believed to be responsible for this new extrinsic component of reversible pyroelectricity

The large reversible pyroelectric effect is a promising phenomenon for developing new pyroelectric devices