Advances in the characterisation of domain switching in ferroelectric ceramics

In ferroelectric materials, extrinsic contributions such as domain wall vibrations, domain switching, and interphase boundary motion contribute to fatigue and aging, nonlinearity, and hysteresis in the piezoelectric response. It also affects the deformation behaviour, and influences the fracture mechanics. The most prevalent extrinsic contribution is ferroelectric/ ferroelastic domain switching. Recent advances in diffraction techniques offer many opportunities for novel characterisation of domain switching and its influence on macroscopic properties. This paper presents the results of two such techniques which have been used to characterise extrinsic mechanisms in situ in a soft lead zirconate titanate (PZT) ceramic. In the first example, stroboscopic, time-resolved neutron diffraction is used to represent the ferroelectric/ferroelastic domain switching during a single cycle of a 1 kHz unipolar electric field with a magnitude of half of the coercive field. In the second example, high-energy X-ray microdiffraction is used to measure the spatial distribution of ferroelastic domain switching around a crack tip in transmission geometry under an applied stress intensity factor of K ₁=0.71 MPa•m^1/2.