In-situ observation of fatigue crack growth for 001 -oriented rhombohedral Pb(Mg1/3Nb2/3)O3-PbTiO3 ferroelectric single crystal

In-situ observation of the electrically induced fatigue crack growth is carried out for 001 -oriented (Pb(Mg1/3Nb2/3)O3)0.72-(PbTiO3)0.28 (PMN-28PT) ferroelectric single crystals under alternating electric field. It is found that apparent crack growth takes place even though the peak value of the applied electric field is below Ec. The crack propagation is a repeated process of advancement in small increments, followed by a sudden increase in the crack length. When the crack tip pops-in, there is a tendency for branching. The test data suggest that the variation of the crack boundary condition may contribute to the observed electrically induced crack growth behavior