Room-temperature creep of soft PZT under static electrical and compressive stress loading

This study focuses on the experimental investigation of time-dependent effects of a commercial piezoceramic material at room temperature. Specimens in the unpoled or poled state were subjected to an electric field or a compressive stress loading increasing from zero and then kept constant at a certain level. Due to ferroelectric or ferroelastic domain switching, significant nonlinearity and hysteresis were observed in the overall polarisation and strain response. In particular, the material exhibited a creep behaviour as the external loads applied were kept constant for extended periods of time. This creep was of the primary type and could be quantified approximately using the Andrade power law. For an initially unpoled specimen, most pronounced electrical creep was observed when holding the field close to the coercive field. Under purely mechanical loading, the material exhibited the greatest time-dependent effects at a stress level near the coercive stress.