Ferroelectric Polarization Fatigue in PZT-Based RAINBOWs and Bulk Ceramics

The ferroelectric fatigue behavior of high‐displacement reduced and internally biased oxide wafer (RAINBOW) actuators was investigated and compared with that of conventional bulk ceramics. Piezoelectric lead zirconate titanates (PZT‐5H and PZT‐5A) as well as electrostrictive lead lanthanum zirconate titanate (PLZT 9/65/35) materials were studied. Piezoelectric bulk ceramics experienced a 25% decrease in remanent polarization over 10–8 switching cycles, whereas RAINBOW polarization degraded by 33%–53%. Bulk ceramic and RAINBOW electrostrictors both fatigued only 8%. Bulk ceramics fatigued as a result of reorientation of the polar axes away from the electric‐field direction. RAINBOW fatigue was believed to have been caused by degradation at the interface between the oxide and chemically reduced layers.