FATIGUE RESISTANCE IN LEAD-ZIRCONATE-TITANATE THIN FERROELECTRIC-FILMS - EFFECT OF CERIUM DOPING AND FREQUENCY-DEPENDENCE

We demonstrate improvement in fatigue resistance and other ferroelectr ic properties through cerium doping in sol-gel derived lead zirconate titanate thin films. We have studied frequency dependence of fatigue b ehavior and show that the loss of polarization due to fatigue follows a universal scaling behavior with N/f(2), where N is the number of swi tching cycles and f the frequency. The origin of the scaling is attrib uted to the drift of oxygen vacancies, which is the rate limiting proc ess in the growth of the interface layer responsible for fatigue. Empi rical fits for both undoped and cerium-doped samples show that switcha ble polarization follows stretched exponential decay with time or N/f. Cerium doping is shown to improve fatigue resistance by impeding the motion of oxygen vacancies. (C) 1996 American Institute of Physics.