Degradation of piezoelectric and dielectric relaxation properties due to electric fatigue in PLZT ferroelectric capacitors

The fatigue properties of ferroelectric ceramics due to electric loading we re investigated. With the decrease of switchable polarization, the piezoele ctric and dielectric relaxation properties were both found to be deteriorat ed heavily. The G-B circles decreased to a smaller one indicating the weake ning of piezoelectric resonance. The measurement of complex impedance showe d that the bulk resistance also degraded after fatigue with the decreasing of relaxation time. Oxygen vacancy was believed to be responsible for the f atigue properties by analyzing the activation energy variation. The mechani sm for fatigue was suggested according to the possible relationship between the degradation of piezoelectric and dielectric properties. (C) 2001 Elsev ier Science B.V. All rights reserved.