Defect structures and fatigue in ferroelectric PZT thin films

A thermally stimulated current (TSC) technique has been used to characterize natural and electric-field-induced defect distributions in PZT (lead zirconate titanate) films. The principal defects give rise to TSC peaks near 400 K and 500 K, with defect concentrations of about 10/sup 21/ cm/sup -3/ and an activation energy of about 0.8 eV. Changes in the defect structures as a function of the number of switching cycles and processing conditions are described, and their relationship to fatigue are discussed. It is suggested that the defects distributions measured by TSC arise from extended defects rather than from point defects. Domain splitting and pinning as a result of such defects generated during polarization reversals may account for fatigue in PZT films.<
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