Coexisting depinning effect of domain walls during the fatigue in ferroelectric thin films

Appropriate time relaxation before a driving pulse of domain switching can improve fatigue endurance in Pb(Zr,Ti)O-3 thin films. The effect is more evident under a relaxation voltage close to a coercive voltage (V-c) in the same voltage polarity to the driving pulse, in contradiction with previous investigations of domain-wall pinning more effectively under driving voltages close to V-c. Pinning and depinning of domain walls are identified to coexist during bipolar voltage stressing of the films and both modeled per cycle on the basis of charge injection at high frequencies and mobile charge separation at low frequencies. (c) 2006 American Institute of Physics.