Domain switching in ferroelectric ceramic materials under combined loads

An experimental study to investigate the various characteristics of the nonlinear behavior of a ferroelectric ceramic material under different electrical and mechanical loading conditions is reported. The nonlinear strain behavior under different loading conditions is obtained and used for studying the effect of residual stress, developed in the ferroelectric ceramic material during manufacture, on domain switching under applied loads. First, the behavior at low electric field and mechanical stress are studied by comparing the linear piezoelectric properties measured from the strain responses under mechanical and electrical loading with those measured by resonance method. This is followed by an investigation on the mechanism of polarization reversal due to cyclic electric field. Based on the observed large magnitude of strain and the comparison of the magnitude of the sum of transverse strains with the magnitude of strain in the poling direction it is concluded that polarization reversal due to cyclic electric field in the ferroelectric material at morphotropic phase boundary is the result of two successive 90 degrees domain switchings of the individual domains rather than a direct 180 degrees domain switching. Finally, two types of combined loading experiments were conducted to investigate the residual stress effect on the mechanism of domain switching. The behavior under combined loading shows many interesting characteristics. An attempt is made to explain the characteristics of the nonlinear ferroelectric behavior observed in the present experimental study based on the effect of residual stress on domain switching. (C) 2005 American Institute of Physics.