Partial dislocations at domain intersections in a tetragonal ferroelectric crystal

Abstract

Domain behaviour under electric cycling was examined by transmission electron microscopyin a -oriented 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 ferroelectric crystal. Prior to electric cycling, the crystal contained two nonparallel sets of90° domain walls along the two {110} planes. For the most part, the domain walls remained planar,dividing the crystal into highly regular domain strips. As two nonparallel domain wallsapproached each other, the domain width tapered down to avoid full contact. Upon repeatedelectric cycling, the domains were forced into full contact, resulting in direct intersections of90° domain walls and charged wall segments along the domain intersection. At the domainintersection, partial dislocations were observed along with a stacking fault on a plane. These dislocations had a Burgers vector of and were of predominantly screw type. It is suggested that the partial dislocationsresulted from a shear displacement along [101] in the crystal as the domain switched itspolarization to form the intersection.