Stress assisted electrical poling of ferroelectrics

Poling of piezoelectric ceramics is required to induce piezoelectric behaviour. A new method has been designed to apply a transverse mechanical stress while applying an axial electrical field. The effect of this combined loading method on polarization and piezoelectric coefficient is studied as a function of loading path, electric field and mechanical stress. Due to this treatment, the electrical poling field is strongly reduced. Also, the effect of a transverse mechanical stress on the coercive field during bipolar electrical cycling is considered. The results are discussed in terms of 180deg domain switching and non -180deg domain switching. This method has mainly been applied to PZT with selected results on other materials. The transverse radial mechanical stress on cylinders is applied by using the Poisson effect. This ensures a very homogeneous stress transfer to the piezoceramic.