In situ TEM study of electric field-induced microcracking in piezoelectric single crystals

Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN–PT) single crystals exhibit ultrahigh piezoelectric coefficients and are the most promising candidates for the next generation of transducers, sensors and actuators. One critical problem that limits the device performance using these crystals is the fatigue degradation associated with the electric cycling. Microcracking is the most serious degradation phenomenon in these piezoelectric materials. In this work, in situ transmission electron microscopy (TEM) was used to investigate electric field-induced microcracking in PMN–PT single crystals. Microcrack initiation from a fine pore under a cyclic field and field-induced ferroelectric domain boundary cracking were directly observed in the piezoelectric single crystals.