Shock-induced polarization of a ferroelectric ceramic

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Abstract
Electric fields existing in shock‐wave‐compressed specimens of poled ferroelectric ceramics are caused by both the piezoelectric effect and a randomization of the domains aligned in the poling process. The contribution of these effects to the electric field is governed by the dielectric equation of state of the material. In general, even the form of this equation of state is uncertain for the large electric field and stress values encountered in the shock‐compression process. In this work a form is assumed for the equation giving the shock‐induced polarization. It includes terms representing, respectively, a linear dielectric, a ferroelectric including the stress and field dependence of the remanent polarization, and a piezoelectric whose coefficients are proportional to the remanent polarization. An important prediction of this relation is that shock waves can increase the remanent polarization of a partially poled specimen. This effect has been observed, and the conditions under which it occurs are used to evaluate the equation of state of a representative material, PZT 65/35.