Electrically-Induced Strains in Sn-Modified Lead Zirconate Titanate

Incommensuate antiferroelectric tin-modified lead zirconate titanate ceramics, PbNb0.02[(Zr1-x,Snx)1.yTiy]0.98O3, have been studied by Sawyer-Tower polarization and electrically-induced strain (ε-E) techniques. Sawyer-Tower polarization studies revealed antiferroelectric-ferroelectric (AFE-FE) P-E loops. Investigations then revealed that the electrically-induced strain associated with the AFE-FE transformation was not realized until field strengths significantly above that required for polarization saturation. It is believed that the electrically-induced strain is decoupled from the polarization due to AFE-FE switching by the modulation of the phase of a <110> incommensurate structure. At field strengths above saturation, the commensurate rhombohedral ferroelectric state is believed to be induced from an incommensurate orthorhombic ferroelectric, and the electrically-induced strain is then realized.