DISCRIMINATION BETWEEN BULK AND INTERFACE SCENARIOS FOR THE SUPPRESSION OF THE SWITCHABLE POLARIZATION (FATIGUE) IN PB(ZR,TI)O-3 THIN-FILMSCAPACITORS WITH PT ELECTRODES

A simple and reliable method which allows one to distinguish between t he two major microscopic scenarios for the suppression of the switchin g polarization (P-r(s)), i.e., pinning of ferroelectric domain walls ( DWs) through the Pb(Zr,Ti)O-3 film (PZT) (bulk scenario) and inhibitio n of the growth of opposite domains due to the nucleus suppression at the electrode interfaces (interface scenario), is proposed. In additio n, a new electric treatment able to significantly suppress P-r(s) in P t-PZT-Pt ferroelectric capacitors (FECAPs) of thicknesses above 1.4 mu m, was discovered and studied. It consists of the application of an e xternal alternating electric field (E-e) which cycles the polarization at very low frequency (1.7 mHz). After only 10-20 cycles, P-r(s) can be suppressed by a factor of 10. The same FECAP, when subjected to E-e at higher frequency (30 kHz), endures at least 10(8) switches, before attaining an equivalent P-r(s), suppression (hereafter called fatigue ). The fatigued states obtained with the two different procedures appe ar to be different. In the first case (slow cycling) it is suggested t hat the suppression of P-r(s) is related to the DW pinning scenario, w hereas in the second case-which corresponds to the normal fatiguing pr ocedure-it is related to the interface scenario. (C) 1998 American Ins titute of Physics. [S0003-6951(98)01619-2].