The low frequency relaxor properties of ferroelectric PZT-4 studied by DMA

Abstract

Relaxation makes ferroelectrics a critical component in sensors, actuators and ultrasound devices, with large electromechanical coupling effects. Although various studies of ferroelectric relaxation have been undertaken, much remains to be investigated regarding the related the properties and mechanisms, with limited studies involving low frequency relaxation characteristics. In this study, an alternative mechanical method using a dynamic mechanical analyzer (DMA) was applied to investigate the low frequency relaxor behavior of PZT-4 ceramics, compared with conventional electric method. Ferroelectric to paraelectric phase transitions were clearly detected and an obvious low frequency relaxor behavior was characterized, induced by Debye relaxation. Then, the activation energy of each relaxation peak and relaxation limit time was theoretically analyzed using the Arrhenius relationship. In addition, the switching of 90° domains was shown to be responsible for relaxor behavior. In contrast, no low frequency relaxor behavior was detected by dielectric measurements, which meant that the mechanical method was more sensitive to internal structural changes. This study deepened the current knowledge on relaxor ferroelectrics, and offered the potential for provide new insights into the investigation of low frequency relaxor characterization.