Temperature-dependent ferroelastic switching of soft lead zirconate titanate

The longitudinal strain and polarization of a soft polycrystalline ferroelectric ceramic (lead zirconate titanate, PZT) were measured under uniaxial compressive stress at elevated temperatures utilizing a novel testing fixture. Ferroelectric ceramics have not previously been characterized under these conditions due to experimental complexity. In addition to nonlinear macroscopic constitutive behavior, the linear elastic moduli have been measured throughout the loading cycle, allowing for the determination of the relative contributions from the linear and nonlinear ferroelastic behavior as a function of stress and temperature. Experimental results show a strong temperature dependence of ferroelastic switching. The ferroelastic properties of unpoled and poled materials for temperatures up to the Curie point are contrasted with the spontaneous strain, elucidating the role of tetragonality in ferroelastic switching. When thermal changes are considered, marked changes in the maximum strain are observed. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.