FIELD-ADJUSTED SUPPRESSION OF THE SWITCHING POLARIZATION IN FERROELECTRIC PZT THIN-FILMS WITH PT-ELECTRODES

A surprising non-cumulative effect of the degradation mechanism (fatig ue) of the switched polarization (P-r(s)), was observed in MOCVD and s ol-gel prepared Pb(Zr0.47Ti0.53)O-3 (PZT) ferroelectric thin films cap acitors (FECAP) with Pt-electrodes. This effect is a manifestation of the ability of the suppression mechanism of P-r(s) to self-adjust to t he fatiguing field. Experimentally this was shown by performing two co nsecutive fatigue procedures on the same capacitor. The field used in the first procedure was 15 MV/m, which corresponds to about two times the coercive field (E-c). During this procedure, P-r(s) was reduced (f atigued) by approximately a factor of 10. For the successive fatigue, the field used was twice the first one, i.e., about 4xE(c). During the latter procedure, the previously suppressed P-r(s) was first signific antly recovered and then suppressed again as the FECAP would have been virgin and directly fatigued at E approximate to BxE(c). From this re markable feature and other related results it was concluded that the m icroscopic mechanism must have a substantial reversible character and the peculiarity to adapt to the used fatiguing field (field self-adjus ting).