Charge pumping and pseudopyroelectric effect in active ferroelectric relaxor-type films

Abstract

Unidirectional charge flow was observed in potassium tantalum niobate, ${\mathrm{KTa}}_{0.6}$${\mathrm{Nb}}_{0.4}$${\mathrm{O}}_{3}$, films. These films of relaxor-type diffuse phase transition material were formed by metalorganic deposition and had a polarization gradient normal to the surface of the films. Novel charge pumping was observed in the active operation of simple two-terminal structures by excitation with periodic, strong electric fields. Such operation also showed a large pseudopyroelectric response. Effective pyroelectric coefficients as large as 2\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$ C/${\mathrm{cm}}^{2}$ \ifmmode^\circ\else\textdegree\fi{}C have been obtained.