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Wurtzite ferroelectric materials are promising candidates for energy‐efficient memory technologies, particularly for applications requiring high operating temperatures. Asymmetric wake‐up behaviors, in which the polarization reversal depends both on polarity and cycle number for the first few dozen cycles, must be better understood for reliable device operation. Here, the detailed analysis of the asymmetric wake‐up behavior of thin film Al_0.94B_0.06N was performed combining time‐resolved switching measurements with Rayleigh analysis, piezoelectric measurements, and etching experiments of progressively switched samples. The analysis shows that the gradual opening of the polarization hysteresis loops associated with wake‐up is driven by a gradual increase in the domain‐wall density and/or domain‐wall mobility with electric field cycle to the polarity opposite to the growth polarity. The insights of this discovery will help to guide interface and polarity design in the eventual deployment of reliable devices based on these materials.

Coupon specimens of poled and depoled lead zirconate titanate (PZT) are examined under combined stress wave and electric loading conditions. Mode‐I crack initiation and fracture behavior is examined using ultrahigh‐speed imaging and two‐dimensional digital image correlation. The dynamic critical stress intensity factor () is extracted using measured displacement fields ahead of the impulsively loaded crack tip, and compared between poled and depoled plates that were either under no electric field, positive 0.46 kV/mm electric field, or negative 0.46 kV/mm electric field. Poled specimens had a poling direction and applied electric field direction normal to the crack front. The addition of an electric field resulted in a crack‐enhancing effect, where the dynamic fracture toughness of poled specimens under0.46 kV/mm was almost half that of samples with no electric field. Depoled samples experienced almost no change in dynamic fracture toughness with the addition of an electric field.